Retrofitting Earthquake-Damaged RC Structural Walls with Openings by Externally Bonded FRP Strips and Sheets
Bing Li1;Kai Qian,A.M.ASCE2;and Cao Thanh Ngoc Tran3
Abstract:The majority of research studies on the behavior of reinforced concrete members with externally bonded fiber reinforced polymer (FRP)sheets have been focused on beams,columns,and beam-column joints.However,limited experimental studies have been conducted to investigate the performance of structural walls retrofitted by wrapping FRP strips or sheets,especially on structural walls with openings.The validated retrofitting schemes for strengthening damaged walls without openings may not be suitable for walls with openings.Therefore,a series of experimental studies were carried out at Nanyang Technological University,Singapore,to study the effectiveness of the proposed repair and strengthening schemes in recovering the seismic performance of the damaged walls with irregular or regularly distributed openings. The strut-and-tie approach was utilized to design the repair schemes.The repaired walls managed to recover their strength,dissipated energy, and stiffness reasonably,indicating that the strut-and-tie approach can be a good design tool for FRP-strengthening of structural walls with openings.Moreover,the shear and sliding capacities of repaired walls were enhanced by using fiber anchors.The repaired walls failed primarily because of debonding of the fiber reinforced polymer at the base of the walls.DOI:10.1061/(ASCE)CC.1943-5614 .0000336.?2013American Society of Civil Engineers.
CE Database subject headings:Earthquakes;Seismic effects;Fiber reinforced polymer;Walls;Openings;Bonding;Rehabilitation. Author keywords:Repair;Fiber reinforced polymers;Wall;Opening;Strut-and-tie;Reinforced concrete.
Introduction
RC structural walls play a very important role in carrying lateral loading and resisting drift in tall buildings.Piercing a wall with openings may significantly influence its behaviors,such as chang-ing its force transfer mechanism,deducting its strength and stiffness,and decreasing its ductility level.Although walls with openings have been studied by some researchers(Yanez et al. 1992;Ali and Wight1991;Marti1985),the effects of the regular and irregular openings on the seismic performance of RC walls are still not fully understood.Thus,two3-story reinforced concrete model walls,scaled to one-third,were tested under reversed cyclic lateral load.Sspecimens W1and W2were designed with similar dimensions and details as Yanez et al.(1992)and Marti(1985), respectively.Moreover,for detailed results of these two control specimens refer to Wu(2005)and Zhao(2004),respectively.The goal of this paper is to investigate whether the damaged walls with openings could restore their seismic performances after proposed retrofitting.Fiber reinforced polymers(FRP)were utilized in this study because of their high strength-to-weight ratios,corrosion resistance,ease of application,and tailorability.In addition,the orientation of the fiber in each ply can be adjusted to meet specific strengthening objectives(Engindeniz et al.2005).
Although numerous research studies had been conducted to strengthen or repair the structural components,such as beams,col-umns,and beam-column joints(Lam and Teng2001;Teng and Lam2002;Pampanin et al.2007;Teng et al.2009;Li and Chua 2009;Li and Kai2011;El-Maaddawy and Chekfeh2012),there are limited experimental studies that were conducted to investigate the effectiveness of FRP retrofitting the damaged RC structural walls, especially for walls with openings.
Neale et al.(1997)have tested wall-like columns that were strengthened using FRP,including wall-like columns with different arrangements of externally bonded FRP reinforcements subjected to uniaxial compression only.Lombard et al.(2000)performed rehabilitation of structural walls using carbon fiber reinforced polymer(CFRP)externally bonded to the two faces of the wall to increase its flexural strength.The use of unidirectional carbon fi-bers with the fibers aligned in the vertical direction increased the flexural capacity and precracked stiffness and the secant stiffness at yield.Several nonductile failure modes of the wall were attributed to the loss of anchorage or tearing of the fibers.Antoniades et al. (2003)tested squat RC walls up to failure and then repaired them using high-strength mortar and lap-welding of fractured reinforce-ment.The walls were subsequently strengthened by externally bonded FRP sheets as well as by adding FRP strips to the wall edges.FRP increased the strength of the repaired walls by approx-imately30%compared with traditionally repaired walls.However, the energy dissipation capacity of the control walls could not be restored completely.Li and Lim(2010)retested four seismically damaged structural walls(two low-rise walls and two medium-rise walls)after conventionally repaired and strengthened by wrapping with FRP sheets.It was reported that the repaired and strengthened walls were able to restore the performance of the damaged RC walls.This repair method is relatively easy.
1Associate Professor and Director,Natural Hazards Research Centre at Nanyang Technological Univ.,Singapore639798(corresponding author). E-mail:cbli@https://www.doczj.com/doc/c42588714.html,.sg
2Research Associate,Natural Hazards Research Centre at Nanyang Technological Univ.,Singapore.E-mail:qiankai@https://www.doczj.com/doc/c42588714.html,.sg 3Lecturer,Dept.of Civil Engineering,International Univ.,Vietnam National Univ.,Ho Chi Minh City,Vietnam.E-mail:tctngoc@hcmiu .edu.vn
Note.This manuscript was submitted on February24,2012;approved on September25,2012;published online on September27,2012.Discus-sion period open until September1,2013;separate discussions must be submitted for individual papers.This paper is part of the Journal of Com-posites for Construction,V ol.17,No.2,April1,2013.?ASCE,ISSN 1090-0268/2013/2-259-270/$25.00.
The available research conducted on the rehabilitation of walls using FRP was promising;however,the repaired walls were with-out openings in the previous tests and the effectiveness of repairing RC walls with openings(irregularly and regularly distributed)by a similar method needs to be further investigated.Understandably, some of the repair and strengthening schemes for walls without openings may not be suitable for the repair of damaged walls with openings.For example,wrapping integrated FRP sheets on the face of the walls cannot be used in retrofitting of walls with openings. Bonding discrete FRP strips or sheets could be a good alternative to recover the seismic performance of the damaged walls with an opening.However,the direction,width,and the number of layers of each FRP strip had to be determined properly.The strut-and-tie model was a truss model of a structural member,or of a D-region in such a member,made up of struts and ties connected at nodes and capable of transferring the factored loads to the supports or to adjacent B-regions(ACI2008).Thus,this study employed the strut-and tie model to determine the direction,width,and number of layers of the individual FRP strip.
Strut-and-tie models have been used intuitively for many years in design work,whereby complex stress fields inside a structural member arising from applied loads are simplified into discrete com-pressive and tensile force paths.With the aid of the strut-and-tie model,a better visualization and understanding of the distribution of internal force and the mechanism of force transfer can be achieved.The research program in this study taps this advantage to propose FRP-strengthening techniques for RC structural walls with openings.
Experimental Program
The first part of the paper briefly presents the seismic behavior of two one-third scaled RC structural walls as control specimens that were tested under reversed cyclic load.After studying the fail-ure modes of the control specimens,the damaged RC walls were repaired by epoxy injection,the loose concrete was replaced by high strength mortar and subsequently strengthened by externally bonded FRP strips,which were designed according to the proposed strut-and-tie models.Then these repaired specimens were retested under similar loading conditions.
Description of Control Specimens
Control Specimen W1had irregularly distributed openings.The dimensions of Specimen W1are given in Fig.1and had three subassemblies as follows:(1)the top beam,(2)the web,and (3)the foundation beam.W1was2,000mm wide,2,300mm high, and120mm thick,with an aspect ratio of approximately h w=l w?1.27,where h w?2;540mm was the vertical distance from the lateral loading point to the wall base(Fig.1),whereas l w?2;000mm was the width of the wall.The size of each irregu-
larly distributed opening was600mm×600mm.Two deep flanges(120mm×400mm)were added to the side edge of the wall.The reinforcement details are also presented in Fig.1.The reinforcements applied in a certain place are denoted according to their quantity,steel types,and diameters as illustrated in Fig.1. For example,6T10means there are six T-bars whose diameters are 10mm.High yield strength steel deformed bars and the mild steel plain bars are indicated as T-bars and R-bars,respectively.
Control Specimen W2had regularly distributed openings.The size of each regularly distributed opening was400mm×400mm. Similar to W1,W2also had three subassemblies:the top beam,the web,and the foundation beam.W2was2,600mm wide,2,300mm high,and120mm thick,with an aspect ratio of1.0.Thus,both
W1Fig.1.Dimensions(mm)and detailing of Specimen
W1 Fig.2.Dimensions(mm)and detailing of Specimen W2
and W2are low-rise or squat walls.However,the cross section of Specimen W2is rectangular and without flanges.The vertical and horizontal reinforcement details are shown in Fig.2.The web of the wall was divided into beam,column,nodal,and panel zones based on the openings,as shown in Figs.1and 2.Material Properties
Ready-mix concrete,which had a characteristic strength of 30MPa,13mm maximum size aggregate,and a slump 100mm,was used
to cast the specimens.The measured compressive strength f 0c
of Specimens W1and W2are 36.9MPa and 39.1MPa,respectively.A high yield steel bar with nominal yield strength of 460MPa and a mild steel bar with nominal yield strength of 250MPa were used.The properties of the steel bars and FRP are shown in Tables 1and 2,respectively.Test Setup
The testing rig,shown in Fig.3,consisted of two systems:an in-plane loading system and an in-plane base beam reaction system.The in-plane loading system included a double action hydraulic jack and four steel beams.The jack had a capacity of 2,000kN in compression and 1,200kN in tension.The stroke of the jack was 405mm.The steel frame was arranged in a configuration such that two-direction lateral loadings could be applied to the wall.Four high strength steel rods were preset in the loading beam to enable lateral loading to be applied on the top loading beam.The base beam reaction system was designed to resist the rotation and sliding of the wall specimen when the load was applied.They were attached to a strong floor by high strength rods.Reaction foot-ings were provided to balance the lateral loading.A prestress scheme was applied to every steel rod so that the rotation and slid-ing during the test could be restrained efficiently.No axial force was applied in the test because the lateral force transfer mecha-nisms in the walls were the focus in this study and low axial load levels are common for low-rise shear walls in practice.
Instrumentation and Test Procedure
To record data from the experimental setup,a dynamic actuator,strain gauges,linear variable displacement transducers (LVDTs),and displacement transducers were utilized.An LVDT was set up at the center of the top beam to measure the top drift.LVDTs were arranged vertically in the walls to detect the flexural deformation.The panel shears deformations measured by the LVDTs distrib-uted along diagonal directions of the panels.Local strains in the reinforcement bars were measured by electric resistance wire strain gauges (TML FLA-5-11-5LT),which were installed on the bars before casting of the specimens.
The specimens were tested under cyclic lateral loading,which was applied to the top of the wall.The loading cycles were dis-placement-controlled in which the top displacement was expressed as a factor of the vertical height of 2,540mm from the base of the wall to the point where the load was applied.The factors used were 1=2;000,1=1;000,1=600,1=400,1=300,1=200,1=150,1=100,1=75,and 1=50multiplied by the vertical height of 2,540mm from the wall base to the point where the load is applied.The typical loading procedures are illustrated in Fig.4.
Seismic Behavior and Failure Modes of the Control Specimens
Control Specimens W1and W2had been tested to failure and sus-tained severe damage.Specimen W1developed a sliding failure at the bottom panel,but the sliding face was approximately 200mm above the base of the wall.The damage sustained by Specimen W1included severe concrete crushing and spalling at the bottom
Table 1.Measured Steel Bar Properties Types Yield strength f y (MPa)Ultimate strength
f u (MPa)Specimen W1W2W1W2R6308293428405R10385382502481T10480467545541T13493493581581T20
512
512
607
607
Table 2.Tyfo Fiberwrap Composite System
Parameter
Properties a
GFRP with epoxy,Tyfo SEH-51A composite CFRP with epoxy,Tyfo SCH-41composite Type of FRP
Unidirectional GFRP sheet
Unidirectional CFRP sheet
Ultimate tensile strength in primary fiber direction
575.0MPa 986.0MPa Ultimate tensile strength 90degrees to the primary fiber direction 25.8MPa 40.6MPa Elongation at break 2.2%
1.0%
Tensile Modulus 26.1×103MPa
95.8×103MPa
Laminate thickness
1.3mm
1.0mm
a
Property values given are based on test value by supplier (FYFE Asia Pte.Ltd in
Singapore).
Fig.3.Typical experimental setup
flanges and the right bottom corner of the bottom panel.Further-more,the shear force had to be sustained by the bottom panel because the bottom right column,where the concrete cracked severely,could not bear the shear force.When the sliding face was formed,the strength of the wall decreased significantly.The severe sliding shear failure that occurred in W1could be attributed to several causes.First,low-rise (squat)shear walls had a much higher propensity for shear failure compared with slender walls.Second,boundary elements (deep flanges)significantly increased the flexural strength of a wall but simultaneously jeopardized the shear strength compared with a rectangular wall.Third,piercing the wall with openings further weakens its shear strength.Moreover,most of the steel bars in the flanges buckled,and some steel bars were fractured.The final crack pattern of Specimen W1is illus-trated in Fig.5.On the other hand,Specimen W2had obvious movement observed along the diagonal cracks that appeared on every panel.The four bottom columns were damaged severely but no sliding shear failure was observed.In particular,extremely severe concrete crushing was observed at the two columns near to the bottom edges.Significant spalling of the concrete cover and buckling of the steel bars were also observed.The final crack pattern of Specimen W2is illustrated in Fig.6.Strut-and-Tie Models
As mentioned previously,strut-and-tie models were utilized to aid in designing the strengthening schemes of the damaged specimens
because of the openings,which changed the load path and stress distribution significantly.In general,a strut-and-tie model would simplify a structural member as a hypothetical truss.The compres-sive concrete struts and tensile steel ties joined together at the nodal zones.The following assumptions were made in the development of the strut-and-tie models of Specimen W1:(1)the beam and column zones (as shown in Figs.1and 2)were subjected to axial tensions when the entire zones were under tension in the load paths;(2)all reinforcements in the beam or column zones were lumped into one tie,and its position was located in the centriodal axis of the reinforcement lumped into it;and (3)the strut position was deter-mined by keeping the concrete compressive stress in it lower than the strength limitations suggested by Schlaich et al.(1987),which
is 0.68f 0c
for a concrete strut with cracks parallel to it or 0.51f 0c for a concrete strut with skew cracks.According to these assumptions,the tie area and its influence region can be easily determined.However,the real geometry of a strut may sometimes be difficult to illustrate because the strut may represent a bottle-shaped stress field.In normal practice,the strut can be idealized into a prismatic or uniformly tapered shape according to the geometry of the nodal zone.For a concentrated node,its geometry can be clearly defined by the boundary of the bearing plate or tie.In the case of walls with an irregular opening where generally no bearing plate presents,the geometries of the nodes and struts are determined based on the divisions of the beam and column zones and the posi-tion of the openings.For example,the details of the strut,nodes,and compressive stress of each strut of Specimen W1are presented in the Appendix.The greater details of the experimental results of the strut-and-tie models are described in Wu (2005)and Zhao (2004)for Specimens W1and W2,respectively.As the load path and force magnitude of the struts and ties are the most important factor considered in the FRP retrofitting design,the load path and force magnitude of Specimens W1and W2are illustrated in Figs.7and 8,respectively.In the models,the compression struts were shown as dotted lines,whereas the tensile steel ties were shown as solid lines.The load path of the strut-and-tie model of each specimen was determined based on the crack pattern observed from the tests and the principal stress flows obtained from the numerical analysis.As shown in Fig.7,the strut-and-tie models of Specimen W1in positive and negative loads were different owing to the exist-ence of an irregular opening.However,the strut-and-tie models of Specimen W2were symmetrical in these two load directions as shown in Fig.8.The widths of the FRP strips were calculated according to the load magnitude and were placed in the direction and location of the load paths in the strut-and-tie models.
-60
-40-2002040
600246
8101214161820
Cycle number
T o p L a t e r a l D i s p l a c e m e n t (m m )
1/20001/10001/600
1/4001/300
1/200
1/150
1/100
1/75
1/50
Fig.4.Typical loading
procedures
Fig.5.Typical cracking patterns of Specimen W1after
test
Fig.6.Typical cracking patterns of Specimen W2after test
Repair and Strengthening Schemes
The walls were first visually inspected for cracks and loose concrete.Then,the loose/spalled concrete was removed using hammers and chisels before repairing the cracks.For cracks of width larger than0.3mm but less than20mm,epoxy resin was injected to seal them.For cracks with crack width larger than 20mm but less than50mm,patch repair using a bonding agent and polymer modified cementitious mortar was adopted.The depth of each layer of the patch repair could not exceed20mm.For regions where the depth of the concrete removed exceeded50mm, it was repaired by pumping grout into the damaged region using a pressurized grouting method.The grout consisted of prepacked 20-mm-diameter aggregates mixed with cement treated with super plasticizer,and grout fluidifier was used to achieve high strength and workability.
The specimens were then left to cure for1day because the ep-oxy resin required a minimum of24h for curing.Subsequently, as mentioned previously,the damaged control specimens were strengthened by externally bonded FRP strips aligned along the load path of the strut-and-tie models.The repaired and strengthened wall specimens were denoted RW1and RW2,respectively.Figs.9 and10show the proposed FRP-strengthening schemes of Speci-mens RW1and RW2,respectively.
As shown in Fig.9(a),the tie-strengthening scheme of Speci-men RW1is described as follows:The width and number of layers of the FRP sheets were determined based on the tensile force of the tie determined by the strut-and-tie models(refer to Fig.7).The tensile force of the tie was assumed provided by the externally bonded FRP strips only.Thus,for example,the design width of the glass fiber reinforced polymer(GFRP)strip#1was determined as follows:
W s?
T s=2
f FRP×d FRP
?
248.8×103
2×e575×1.3T
?166mme1T
where W s=design width of the FRP sheet;T s=tensile force of the tie along the FRP sheet(the tie force of strip#1is248.8kN);
f FRP=tensile strength of the FRP sheet;and d FRP=thickness of the FRP sheet(One layer of FRP was assumed in the precedin
g calculation.If the spacing was restrained,more layers of FRP could be designed.)
Thus,a one-layer GFRP sheet with150mm width was applied on both faces of the wall(#1strip).For tie strengthening,the designed FRP strips were applied on the wall in sequence as shown in Fig.9(a).
For strut strengthening(see the Appendix),the strut stresses are normally less than the limitation(0.68f0c)suggested by Schlaich et al.(1987),except for strut QW.However,the influence of the flanges has not been considered in the strut width of the strut QW. Thus,no crushing of the struts was observed in the failure mode of Specimen W1.Similar behavior was observed in Specimen W2. Thus,the strut strengthening primarily relied on the epoxy injection to fill the cracks and external bonded the FRP sheets[as shown in Fig.9(b)].These FRP sheets along the cracks not only improved the effectiveness of the epoxy repairing but also delayed the crack development during the test because the fibers perpendicular to the primary fibers could provide a slight tensile strength(as given in
Fig.7.Strut-and-tie models for Specimens W1
Fig.8.Strut-and-tie models for Specimens W2
Table 2).In the future,to further restore the seismic performance of damaged walls with openings,tie strengthening in conjunction with concrete tensile strength strengthening [bond FRP strips along the direction of principal tensile strength,as shown in Fig.9(c)]was recommended.
For Specimen RW2,similar to Specimen RW1,tie-strengthening strips were first applied on the surface of the wall.The tensile strips were designed based on the magnitude of the tie force as determined by the strut-and-tie models (refer to Fig.8).Fig.10(a)illustrates the final tie-strengthening scheme of Specimen RW2.
However,for strut strengthening,RW2was slightly different from that of Specimen RW1.For RW1,diagonal FRP sheets were applied along the direction of the diagonal struts.For RW2,to evaluate whether resolving the diagonal compressive force of the strut into horizontal and vertical components and applying the FRP strips according to the magnitudes of these components could be an effective alternative method,part of the diagonal struts were strengthened through a pair of vertical and horizontal FRP strips.Fig.10(b)shows the final strut-strengthening scheme on both faces of the wall.
Fig.5shows the failure mode of Specimen W1,indicating that sliding failure was observed at the bottom panel,which was ap-proximately 200mm above the base of the wall.Thus,a one-layer L-shaped GFRP sheet was applied on both faces of the base of Specimen W1(as shown in Fig.11).Similarly,L-shaped GFRP sheets were applied on both faces of the base columns of Specimen RW2.Moreover,for Specimen RW2,GFRP sheets with 400mm width were utilized to wrap each of the bottom columns because severe damage and concrete crushing was observed in these columns (as shown in Fig.6).Moreover,to prevent premature delamination of the L-shaped GFRP sheets,a series of fiber anchors were mounted (the locations of the fiber anchors of RW1and RW2are shown in Figs.11and 12,respectively).The fiber anchor con-sisted of two parts:the anchor bolt and the protruding fibers.The total length of the fiber anchors used was approximately 110mm.The length and diameter of the anchor bolt were approximately 50and 7mm,respectively.First,holes (10mm in diameter)were drilled at a depth of 50mm on the wall faces before the application of the FRP sheets.After the application of the FRP sheets,the anchor bolts were inserted through the epoxy resin into the holes.The protruding fibers were bent and spread out in circles with a radius of approximately 60mm to act as the base of anchorage.To ensure good adherence between the FRP sheets and concrete,the surface was first cleared of dust and any deleterious substances that might act as bond barriers.Sharp edges and protrusions were also removed by mechanical grinding.
Results and Discussion
Failure Modes and Response under Cyclic Loading
After repairing and strengthening of the damaged control speci-mens,the repaired Specimens RW1and RW2were retested under a similar reversed cyclic lateral load,and the test results were illus-trated.For repaired specimens,the lateral displacement was re-peated for two cycles before the drift ratio reached 1.0%.After that,only one cycle of the lateral displacement was applied.However,for the control specimens,the lateral displacement was repeated for two cycles until the failure of the specimens.For Specimen RW1,no visible cracks or debonding were observed during the initial cycles of the test.At the drift ratio of 0.25%,hairline cracking was distributed along the height of the wall.Because the RC walls at this point were wrapped by FRP sheets,the presence of the cracks was inferred from the thin marks in the epoxy resin at the exterior surface of the FRP sheets.At the drift ratio of 0.33%,the breaking of epoxy resin was heard and a horizontal flexural crack formed at the interface of the repair mortar and the anchor block at the right base of the wall.Subsequently,the crack opened substantially.During the first cycle at the drift ratio of 0.67%,the GFRP sheet at the right base of the wall delaminated at the edges,exposing the concrete underneath.Horizontal flexure cracks also started to form at the center of the wall base near the opening.In the second cycle,the GFRP sheet at the left base of the wall
(a)
(b)
(c)
Fig.9.Proposed FRP strengthening schemes for Specimen RW1:(a)tie-strengthening scheme;(b)currently used strut-strengthening scheme;(c)refined strut-strengthening scheme
debonded.As the drift ratio increased,loud cracking resulting from the debonding of the FRP sheets was heard.At the drift ratio of 1.00%,the GFRP sheet delaminated completely from the base. The FRP sheet at the right base of the wall was then completely delaminated.It was obvious that Specimen RW1had a flexural fail-ure,which was concentrated between the base and the foundation.
For Specimen RW2,the breaking of epoxy resin was heard at the drift ratio of0.25%.At the first cycle of the drift ratio of0.50%, visible epoxy resin cracks were observed at the base of the wall. Cracks started to appear at the wall base at the drift ratio of 0.67%.At the drift ratio of1.00%,diagonal cracks on the wall were observed,and the cracks were primarily at the lower part of the wall.As the drift ratio increased,the FRP strips debonded from the wall to the base.A vertical crack was formed,propagating from the base edge upwards,with a crack length of150mm.When the maximum strength was reached,the whole wall tilted forward in the out-of-place direction.
Load-Displacement Hysteresis Responses
Fig.13shows the load-displacement hysteresis loops of the control and repaired specimens.The hysteretic behavior was evaluated in
Note: (Width x layers); Unit (mm)
(b)
Fig.10.Proposed FRP strengthening schemes for Specimen RW2:(a)tie-strengthening scheme;(b)currently used strut-strengthening scheme
Fig.11.Proposed fiber anchorage schemes in the base of the wall of Specimen RW1
terms of lateral resisting capacity and maximum displacement.The lateral resisting capacity of Specimen RW2was significantly higher than the corresponding control Specimen W2in the positive and negative loading cycles,respectively.The maximum peak strengths in each positive and negative cycle of control Specimen W2were 334and 348kN,respectively,and were reached at the drift ratio of 0.50%.For repaired Specimen RW2,the maximum peak strengths
in each positive and negative cycle were 456and 411kN,respec-tively.This indicated that the proposed repair and strengthening schemes were effective for repairing the damaged walls with regu-larly distributed openings.However,for repaired Specimen RW1,the maximum strength was reached at the drift ratio of 0.50%for both the control and repaired specimens.At this drift ratio,the maximum strengths in the positive and negative direction of control Specimen W1were 385and 394kN,respectively,whereas those of repaired Specimen RW1were 411and 308kN,respectively.Thus,the lateral resisting capacity of the repaired specimens was only slightly higher than that of their corresponding control spec-imens in the positive loading cycles,and repaired Specimen RW1did not reasonably recover the strength of Specimen W1in the neg-ative loading cycles.The strengthening schemes of Specimen W1were asymmetrical owing to the irregularly distributed openings.In addition,as shown in Fig.9(b),the FRP sheets were applied on the face of the wall according to the strengthening scheme of the positive load cycle first.Thus,the FRP sheets that were sub-sequently applied for strengthening the wall in the negative loading cycle helped to anchor the previously applied ones and indirectly improved the effectiveness of the strengthening sheets for the pos-itive loading cycle.
Load-Displacement Envelopes
To study the lateral resisting capacity and ultimate displacement capacity of the specimens,a comparison between the envelopes of hysteretic loops of the tested specimens is shown in Fig.14.
Fig.12.Proposed fiber anchorage schemes in the base of the wall of Specimen
RW2
Horizontal Displacement (mm)
L a t e r a l L o a d (k N )
-600
-500-400
-300-200-100100200300400500600
Horizontal Displacement (mm)
L a t e r a l L o a d (k N )
Fig.13.Load-displacement hysteretic loops for control and repaired specimens
-60-50-40-30-20-100102030405060
Horizontal Displacement (mm)
L a t e r a l L o a d (k N )
Horizontal Displacement (mm)
L a t e r a l L o a d (k N )
https://www.doczj.com/doc/c42588714.html,parison of load-displacement envelope of control and repaired specimens
respectively.As shown in the figures,the recorded strain in the fiber was relatively low compared with their fracture strain of 1.0%(10;000με),although the strain gauge reading along the tie-strengthening fibers displayed tensile reading.This was possibly because debonding of the FRP at the wall base prevented the full development of the strength of the fiber in tie strengthening.More-over,because no special anchorage was designed for these FRPs in the wall body,it was predictable that the strength of the FRP strips could not be fully developed.For Specimen RW2,similar to Specimen RW1,all strain readings fell below 350με,which was much lower than the allowable value of 1.0%.Although some of the fiber readings were initially compressive,the majority of the fibers obtained tensile value.As the tie force of each tie only had two sources (steel reinforcement or FRP for tie strengthening),
tensile modulus of the FRP;A frp =cross-sectional area of each FRP;and F tie =tie force obtained from strut-and-tie models.
Conclusions
In the present paper,the strut-and-tie models were utilized to help in designing the strengthening schemes for repairing damaged structural wall with openings.Based on the observations and the experimental results of this study,the following conclusions can be made:
?The proposed strengthening schemes designed by the strut-and-tie models can effectively recover the overall behavior (strength,stiffness,and energy dissipation capacity)of damaged speci-mens with irregularly or regularly distributed openings.It indi-cates that the strut-and-tie models are effective to help design the strengthening schemes for walls with openings.
?Most of the FRP-strain readings indicated that the FRP strips were not fully utilized because the tensile strain was relatively low compared with the fracture strain of the FRP strips.This indicated that the majority of the tie force was still provided by the steel bars.This was primarily because the tests were stopped as a result of debonding of the FRP sheets in the con-nection in between the base wall and the foundation.Moreover,no special anchorage was provided in the FRP strips for tie and strut strengthening.
?In future practice,replacing the integral FRP sheets along the diagonal cracks with several short FRP strips bonded perpendi-cular with the diagonal cracks will strengthen the strut and in-crease the effectiveness of the FRP strips to delay the reopening of the diagonal cracks.
?Fiber anchors were generally effective in improving the sliding capacity of the walls because few areas on the wall base showed failure in anchorage.However,the performance of the repaired specimens could be further improved if the delamination of the FRP sheets could be delayed or prevented,such as by using a steel plate anchorage to replace the fiber anchor in the base of the wall.Moreover,special anchorage provided in the FRP strips for tie strengthening could improve the strengthening effectiveness.
Appendix.Details of the Strut-and-Tie Model of Specimen W1
Fig.19presents the details of the strut and nodes of Specimen W1.The regions of extended nodal zones are also depicted.Tables 3and 4list the primary properties of the ties and struts,respectively.Moreover,Table 5gives the strut width of Specimen W1.The strut width is measured at the narrowest segment of the strut as shown in Fig.19and is the smallest length of a line from a point at the strut boundary extending perpendicular to the axis of the strut.
050100150200250300Drift Ratio (%)
S t r a i n (10-6
)
0.0
0.2
0.4
0.60.8 1.0 1.2
1.4
Drift Ratio (%)
S t r a i n (10-6)
Fig.18.FRP strains on Specimen RW2
0.0
0.2
0.4
0.60.8 1.0 1.2
1.4
Drift Ratio (%)
S t r a i n (10-6
)
Fig.17.FRP strains on Specimen RW1
Acknowledgments
This research was made possible through the support of and collaboration with FYFE Asia Private Limited in Singapore.The significant assistance from Jeslin Quek and Ow Meng Chye of FYFE Asia are gratefully acknowledged.
References
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Fig.19.Details of the modified strut-and-tie models of Specimen W1
Table 5.Widths of Struts of Specimen W1Strut AB BE DG FG KL LQ QW NU MU Width (mm)
265
88
310
170
247
180
92
160
116
Table 3.Main Properties of Ties of Strut-and-Tie Models of Specimen W1Directions Ties Lumped reinforcement Capacity (kN)Loading factor Negative
OD 8R10+2T10313.20.26DJ 8R10+2T10313.20.95AI 6T10220.00.62FH 4T10146.60.27BD 6T10220.00.82EF 4T10146.60.18Positive
KM 8R10+2T10313.20.79MR 8R10+2T10313.2 1.30a NS 4T10146.60.86b LT 6T10220.00.55NQ
6T10
220.0
0.71
a
Assume strut MU carrying all force of tie NQ.b
Assume strut NU carrying all force of tie NQ.
Table 4.Primary Properties of Struts of Strut-and-Tie Models of Specimen W1
Directions Struts Angle
(°)Area (mm 2)Predicted load factor σc max
(N =mm 2)d σc max =f 0
c
Negative
AB
41.531,800 1.3411.20.30BE a 78.710,5600.9022.90.62DG 39.837,200 1.077.700.21FG 58.320,4000.34 4.420.12Positive
KL 38.229,640 1.2713.20.36LQ 53.121,600 1.6723.80.64QW a 77.611,040 1.3638.1 1.03NU 50.519,200 1.11b 17.80.48MU
35.7
13,920
0.87c
19.3
0.52
a
The strut angle is determined by the shear taken by the column it represents.b
Assume strut NU carrying all force of tie NQ.c
Assume strut MU carrying all force of tie NQ.d
Strength developed in the strut when maximum strength of model is reached.
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钢筋混凝土框架结构施工方案 现浇钢筋混凝土框架施工将柱、墙、梁、板等构件在现场按施工图浇筑。 现浇框架混凝土施工时，要由模板、钢筋等多个工种相互配合进行。因此，施工前要做好充分的准备工作，施工中要合理组织，加强管理，使各工种密切协作，以保证混凝土工程施工的顺利进行。 1、施工前的准备工作 （1）接受技术交底 框架混凝土施工前，全体作业人员应接受技术人员必要的技术交底，将 技术部门编制的混凝土工程珠施工方案，在作业层进行全面的理解并实 施。其内容包括： 1）工程概况和特点：框架分层、分段施工的方案，浇筑层的实物工程量材料数量。 2）混凝土浇筑的进度计划、工期要求、质量、安全技术措施等。 3）施工现场混凝土搅拌的生产工艺和平面布置，包括搅拌台（站）的平面布置、材料堆放位置、计量方法和要求等。 4）运输工具和运输路线要相适应。如为泵送混凝土时，对楼面的水平运输通道，应按浇筑顺序的先后，用钢管把输送管架至浇筑区 域。用双轮车运输时，用钢管架好运输通道，高度应离板面30～ 50㎝。 5）浇筑顺序与操作要点，施工缝的留置与处理。 6）混凝土的强度等级、施工配合比及坍落度要求。 7）劳动力的计划与组织、机具配备等。 （2）材料、机具、工作班组的准备 1）检查原材料的质量、品种与规格是否符合混凝土配合比设计要求，各种原材料应满足混凝土一次连续浇筑的需要。 2）检查施工用的搅拌机、振捣器、水平及垂直运输设备、料斗及串筒、备品及配件设备的情况。所有机具在使用前应试转运行。
3）灌注混凝土用的料斗、串筒应在浇筑前安装就位，浇筑用的脚手架、桥板、通道应提前搭设好，并进行一次安全可靠性的检查， 符合要求后方可进行混凝土的浇筑。 4）对砂、石料的称量器具应检查校正，保证其称量的准确性。 5）安排好本工种前后台劳动人员，配备值班电工、翻斗车司机、看护模板及木工和钢筋工、机械修理工、水电工等配套工种作业人 员。 （3）钢筋及水电管线的检查 1）模板检查：模板安装的轴线位置、标高、尺寸与设计要求是否一致。模板与支撑是否牢固可靠、支架是否稳定。模板拼缝是否严 密，锚固螺栓和预埋件。预留孔洞位置是否准确。发现问题应时 回报处理。 2）钢筋的检查：钢筋的规格、数量、形状、安装位置是否符合设计要求。钢筋的接头位置。搭接长度是否符合施工规范要求。控制 混凝土保护层厚度的砂浆垫块或支架是否按要求铺垫。绑扎成型 后的钢筋是否有松动、变形、错位等。检查发现的问题应及时要 求钢筋工处理。检查后应填写隐蔽工程验收记录。 （4）现场的清理工作 1）模板清理：模板底木屑、绑扎丝头等杂物清理干净。木模在浇筑前应充分浇水润湿，模板拼缝缝隙较大时应用水泥袋纸、木片或 纸筋灰填塞，以防漏浆影响混凝土质量。 2）对粘附在钢筋上的泥土、油污及钢筋上的水锈应清理干净。 3）运输路线上的障碍物应妥善处理。 2、框架结构混凝土的浇筑 全现浇框架结构混凝土的浇筑顺序：在一个施工段内，应尽量采用从两端向中间推进，先浇柱、墙竖向构件，后浇梁、板等横向构件。 （1）柱子混凝土的浇筑 1）柱子混凝土灌注前，柱底表面应用高压冲洗干净没有明水后，先浇筑一层5～10㎝厚与混凝土内砂浆成分相同的水泥砂浆（又称
GBF高注合金蜂巢芯 现浇混凝土密肋楼盖施工工法（湘Q/OKDC030） 巨星建筑结构新技术研究中心 长沙巨星轻质建材（集团）股份有限公司 2014年03月
1．此文件为巨星（集团）公司供全国各子公司内部使用文件，与巨星专利技术、产品、方法配套。 ．与巨星（集团）公司有供货合同的关联企业可供参考，但有关各方有保守巨星技术秘密和商业秘密义务。2． 目次 1 总 则 0 2 主要技术特点与施工工艺流 程 0 3 技术要 求 (2) 4 高注合金蜂巢芯安 装 (5) 5 预留预埋设施的施 工 (6) 6 浇筑空心楼盖混凝 土 (6) 7 高注合金蜂巢芯成品保 护 (6) 8 施工中需用的劳动力、机具设备 (6) 9 附录 A 高注合金蜂巢芯进场验收记 录 (8) (9) 高注合金蜂巢芯安装检验批质量验收记录B GBF附录10 GBF高注合金蜂巢芯现浇混凝土密肋梁楼盖施工工法 1 总则 1.1 为了在施工中正确贯彻GBF高注合金蜂巢芯现浇混凝土密肋空腹楼盖的设计意图与技术要求，保证工程质量，针对该技术的关键环节制定本施工工法。 1.2 本施工工法适用于建筑施工现场进行以GBF高注合金蜂巢芯作非拆除式肋间底面外露芯模 的现浇混凝土密肋空腹楼盖施工和工程质量验收。 1.3 本施工工法根据本技术专利权人长沙巨星轻质建材股份有限公司的研究、试验、大量应用资料，并依据国家现行有关法规、标准和规程而编制。 1.4 在按本施工工法进行施工操作与检查时，除应符合本篇条文规定外，尚应遵从国家现行有关建筑施工的标准、规范、规程。 2 主要技术特点与施工工艺流程 2.1 GBF高注合金蜂巢芯现浇混凝土密肋空腹楼盖是一种由现浇混凝土框架暗梁（或明梁）、密 肋梁、肋间现浇板和位于肋间和现浇板底部的非抽芯式高注合金蜂巢芯（一种底面外露芯模）共同组成的楼盖，高注合金蜂巢芯在楼盖中的作用不仅作为非拆式模板，而且高注合金蜂巢芯底板与楼盖底面平齐，可充作肋间吊顶装饰板，使密肋楼盖底部具有无梁板的效果。 2.2 根据柱网、板跨、荷载等的具体要求，由结构设计确定高注合金蜂巢芯的高度、高注合金蜂巢芯楼盖的总厚度、楼盖断面中孔间密肋及暗梁宽度（或明梁的宽度和高度）、梁板配筋等参数。
柱网布置图(水平间距4500，竖向8000,3000，8000) 设计主要内容——确定基础埋置深度；确定地基承载力特征值；确定基础底面尺 寸；确定基础的高度；基础底板配筋计算；绘制施工图（平面布置图、详图） 1、设计资料 (1)地质资料 该地区地势平坦，无相邻建筑物，经地质勘察：持力层为粘性土，土的天然 重度为18kN/m 3，地基承载力特征值ak f =230kN/m 2 ，地下水位在-7.5m 处，无侵 蚀性。 (2)、荷载资料 柱截面尺寸为350mm ×500mm ，在基础顶面处的相应于荷载效应标准组合，由上部结构传来轴心荷载为N=680kN ，弯矩值为M=80kN ·m ，水平荷载为10kN 。（3）、材料选用
混凝土：采用C20（可以调整） 钢筋：采用HPB235（可以调整） 2、计算书要求 计算书包括封面（见统一格式）、正文，要求书写工整、数字准确、图文并茂。 3、制图要求： 完成2张图：1张基础平面布置图，1张详图（包括基础平面图和剖面图）。建议图纸采用A3幅面，手工或CAD 绘制均可，表达要清楚，施工图（图纸折叠成A4大小）要求所有图线、图例尺寸和标注方法均应符合新的制图标准，图纸上所有汉字和数字均应书写端正、排列整齐、笔画清晰，中文书写为仿宋字。 三．课程设计报告内容 1）确定基础埋置深 根据GB50007-2002规定，初步将该独立基础设计成阶梯形，取基础埋置深度d=1.5m ，室内外高差300mm 。基础高度为h =650mm ，基础分二级，从下至上分350mm,250mm 两个台阶；h 0=610mm （40mm 厚的垫层），h 1=350，h 01=310mm ；a 1=1200mm ，b 1=800mm 。 2）确定地基承载力特征值a f 查表得b η=0; d η=1.0所以： a f =ak f + b ηγ（b-3）+d ηγm (d -0.5) =230+0+1.0×18×1.0kN ∕m 2=248 kN ∕m 2 3)确定基础底面面积 计算基础和回填土重G k 时的基础埋深d = 2 1 ?(1.5+1.3）m=1.35m A 0= d f F G a k γ-=35 .120248680 ?-m 2=3.08 m 2 由于偏心不大，基础底面面积按20%增大，即： A=1.2 A 0=1.2?3.08 m 2=3.69 m 2 初步选择基础底面面积A=l b =2.4?1.6=3.84 m 2,且b=1.6m ﹤3m 不需要再对f a
蜂巢芯 1.蜂巢芯工艺流程 现浇混凝土蜂巢芯空心楼盖的施工工艺流程如图1.1： 图1.1 现浇混凝土蜂巢芯空心楼板施工工艺流程
2.施工措施 2.1 模板工程 （1）必须根据楼盖的总厚度、暗梁的宽度与平面具体位置作恒载取值，进行竖向和侧向稳定计算和板面竖向支撑架抗冲切计算设计模板、龙骨与支撑。 本工程蜂巢芯模板支撑体系采用1830×915×18mm厚九夹板，木50×100mm，支撑采用Φ48×3.5钢管。木枋间距不大于200mm，板模铺钉九层板时四周及接头处钉牢，中间尽量少钉或不钉，以利于拆模。模板必须撑牢、拉紧、防止向外倾覆。立杆间距按900mm布置。 （2）模板按照要求一般为起拱2.5%～5.0%，对于不铺设模板的蜂巢芯楼盖，暗梁及边梁底部铺设模板，并应从梁边伸出20公分以上模板，便于蜂巢芯底板同模板的搭接避免该部位的漏浆。框架暗梁及空心板施工时应起拱3.0‰，在大跨度起拱时考虑楼板周边、角部折线处的过渡，起拱量要比常规稍低，模板支撑统一按板底标高搭设。为保证结构标高的准确，在梁底和板底中加设了独立的可调支撑。 （3）由于空心楼板对楼板本身的削弱，所以拆除模板时要求保证混凝土强度达到设计强度的100%。 2.2 蜂巢芯的安放 （1）本工程采用的蜂巢芯规格尺寸为：900*900*350和900*900 *450两种。蜂巢芯模被吊至安装楼层排放前，必须对其外观完好情况逐个检查，蜂巢芯盒体破损不得超过下表2.1所规定的标准，对有可能漏入混凝土物料者，均需进行封补、填塞后，方可铺设。缺损严
重超标者不得使用。 表2.1 蜂巢芯破损容许修补标准 （2）模板安装完毕，验收合格后，对暗梁、盒芯、预埋管、孔等作放线定位。 （3）调整放线，确保蜂巢芯之间，以及与暗梁、墙、柱之间的间距满足设计要求。 （4）蜂巢芯楼盖的预留水电线管盒应尽量布置在肋梁位置。不能布置在肋梁内的预埋盒可在相应位置摆放蜂巢芯及配件，管线布置在肋梁内。 （5）盒芯的摆放原则：从梁边开始向另外一边应按布置平面图摆放标准盒芯，如设计未作要求，蜂巢芯与梁、墙钢筋的净间距≥10mm，与预留孔洞的净间距≥150mm。肋和肋之间采用标准芯，不合模数处采用配套蜂巢芯，<450采用空心圆管.圆管净距不小于50mm,并应采取切实有效的抗浮措施，本工程采用Φ14的铁丝将蜂巢芯盒绑扎在肋梁或框架梁的底筋上。 （6）蜂巢芯在跨边不合模数处安装蜂巢芯配套盒或相应的圆管配件。梁边采用圆管配件或摆放不下蜂巢芯配件而设置实心混凝土区域应设计配置构造钢筋。
用喷射混凝土加固钢筋混凝土框架柱北京虎背口小区3号楼地面以上6层（包括跃层），地下2层，建筑面积4564m2主体结构为全现浇框架结构，其中地上6层及地下一层为纯框架结构，地下二层为框架剪力墙结构。框架级别按二级设计，抗震设防烈度为8度，主体结构混凝土设计强度等级为C28,主要受力钢筋为E级热轧变形钢筋及I级圆钢筋。 该工程主体结构施工至地面4层时，经检验发现地面二层的36根框架柱混凝土强度均未达到设计要求。为此决定对该层框架柱进行加固处理。经用配筋喷射混凝土补强加固后各项指标均达到设计要求，柱表面规则平整，棱角清晰，取得良好效果。现将加固情况介绍如下。 第1章加固设计 该加固设计系根据有关单位对该楼二层框架柱混凝土质量检验报告提供的检验数据及甲方提出的要求为依据。考虑二层所有框架柱实测混凝土强度均未达到原设计要求，且各柱实际混凝土强度差异较大，因而加固设计采用区别对待的原则。经多方案分析比较，最后确定加大原柱（500mM 500mm断面，采用配筋喷射混凝土加固方案。所有二层框架柱断面均加大至600mM 600mm并根据各柱实测混凝土强度增配不同数量的受力筋以达到原设计要求。其加固设计方案分以下4 种类型进行，见表9-8-l 和图9-8-l 、9-8-2 。 第2章技术措施 为提高混凝土粘结力和整体强度，所有被加固的框架柱均需凿除
混凝土保护层，露出原有受力筋及箍筋，对原柱实测混凝土强度低于1 5.0MPa#（即W类柱），柱断面应凿除1/3。并在凿除前在该柱周围设临时支撑，以确保整体结构的施工安全。 钻凿楼板孔时，应尽可能减小对楼板的破坏，孔洞尽量靠近柱边缘。 凿除柱混凝土保护层应避免对其内部受力筋及箍筋的破坏。新增设的受力筋穿过上下层楼板后应与上下层柱端部的受力筋焊接锚固，其锚固长度不小于30cm。 对I、"类柱中新增设受力筋（其中的1根受力筋）穿过楼板至梁底时，此筋不必穿过梁可直接焊在原柱顶部相对应的受力筋上，其焊接长度不小于20cm。 第3章喷射混凝土施工 9-8-3-1 施工机具 该工程喷射混凝土施工机具选用江西生产的ZP-W型转子式喷射札并配备1台12m3/min移动式柴油空压机，干拌合料搅拌利用施工现场混凝土搅拌站原有的一台强制式搅拌机，搅拌好的干拌合料用翻斗车运至施工现场供喷射使用。 为便于施工，喷射机设在被加固框架柱的楼板上，空压机则放在地面靠近该楼一侧固定不动，喷射机可根据喷射部位不同随时移动。 9-8-3-2 原材料及配合比 水泥：冀东水泥厂生产的525号普通硅酸盐水泥。 砂子：选用质地纯正的中粗砂。
结构设计总说明(一 一、总则: Ⅰ.主要设计依据: 1.建筑结构荷载规范 GB50009-2001(2006年版 2.建筑抗震设计规范 GB50011-2010 3.混凝土结构设计规范 GB50010-2010 4.砌体结构设计规范 GB50003-2001 5.建筑地基基础设计规范 GB5007-2011 6.地下工程防水技术规范 GB50108-2008 7.工业建筑防腐蚀设计规范 GB50046-2008 8.岩土工程勘察报告(工号:K2010-0556 Ⅱ.结构类型及安全等级: 1.工程地址: 2.结构类型:本工程为主体五层的钢筋混凝土框架结构,总高度为20.050m 3.建筑结构安全等级:二级;桩基础设计等级:丙级 4.建筑结构的设计使用年限:50年。 Ⅲ.抗震设计: 1.本工程抗震设防烈度:7度;设计地震分组:第一组;设计基本地震加速度值:0.15g。
2.本工程建筑物的抗震设防类别为丙类。 3.本工程建筑物结构抗震等级:框架构造为二级,计算为三级。 4.本工程的抗震构造措施按8度采取,框架按抗震等级为二级进行施工。 5.本工程地基场地类别:四类,属轻微液化场地。 Ⅳ.露面、屋面主要活动部分活载标准值: 1.不上人屋面: 0.050KN/m2 2.上人屋面: 2.00KN/m2 3.办公室: 2.00KN/m2 4.走廊、卫生间: 2.50KN/m2 5.门厅及楼梯前室: 3.50KN/m2 6.会议室: 2.00KN/m2 7.消防疏散楼梯: 3.5KN/m2 8.资料、档案室:2.50KN/m2 9.阳台、挑蓬: 2.5KN/m2 特别注意:使用及施工堆料均不得超过上述荷载值;水箱间及设备房根据相关专业提供荷载设计,严禁兼做其他用途;所有楼面的后期装修荷载不得大于 0.8KN/m2。 Ⅴ.自然条件: 1.基本风压:0.55kN/m2,地面粗糙度:B类 2.基本雪压:0.35kN/m2
框架柱混凝土专项施工方案 一. 承重支架的搭设 钢管支架是在外墙安全防护脚手架的基础上形成一个三排全钢脚手架体系，由于柱子较高，框架梁离天面10米，因此，在脚手架安装时，应严格按照脚手架安装规范进行安装。其方案详见脚手架专项施工方案。 二. 模板的制作和安装 1. 模板的作用和要求：模板是使混凝土构件按设计图几何尺寸成型的模型板。在施工过程中还要求模板能承受模板的自重，钢筋和混凝土的重量，运输工具，施工人员活荷重和混凝土对侧板的压力及振捣机械的动力作用。要求模板和支撑架必须达到以下几点要求： （1）保证结构和构件各部分形状尺寸和相互位置的正确性， （2）具有足够的强度，刚度和稳定性。 （3）构件简单，便于钢筋绑扎，混凝土浇筑和养护的要求。 （4）模板接缝要严密，不得漏浆。 （5）要选材合理，用料经济。 2. 模板选料及制作 （1）. 本工程钢筋混凝土框架柱选用拼合式模板，采用18mm 厚九夹板， 50*70方木和40mm 梁底等材料组成框架柱梁模板。为了保证末班符合要求，便于模板制作安装和拆卸，应该做好放 样工作，这不仅对结构的质量有直接的影响，而且对节约人力物力都有重要意义。
（2）. 根据放样图即可制作模板，在制作过程中必须考虑到模板的作用和要求等因素，结合材料规格，加工技术水平，力求省工，省料。 （3）. 考虑柱梁模拼接拼装方法，加钉部位及数量，达到制模方便，安装简便，拆模方便。 3. 模板安装 模板安装顺序：测量轴线和标高——安装柱模板——调整柱模板的垂直度——加固柱模板——安装大梁底板——侧板——检查轴线偏差——加固梁模板 三. 钢筋的制作与安装 1. 本工程钢筋用量大，规格多，为提高钢筋制作效率，施工程序如下：熟悉配筋图——配料——断料——成型——吊运就位——柱梁筋绑扎——箍筋绑架——验收 2. 钢筋工程质量要点 （1）. 所有钢筋进场必须有产品合格证和试验报告，钢筋的规格，间距根数必须符合设计要求。 （2）. 定期对钢筋班组进行技术交底工作。 （3）. 钢筋的交叉点要用钢丝绑扎牢固，不得有松动和位移现象，箍筋绑扎时应与主筋垂直。 （4）钢筋加工和安装允许偏差按规范施工。 （5）. 钢筋在施工过程中，派专人对钢筋的规格，品种，间距搭接位 置及长度进行复核，验收。不符合要求应及时整改。
XX项目 GBF蜂巢芯密肋梁楼盖施工方案 项 目 效 果 图 编制人: _______________________ 审核人: _______________________ 批准人: _______________________ 中国建筑第二工程局有限公司 20XX年X月X日
目录 一、工程概况 (1) 2、工程概况 (1) 2、空心楼盖部位 (1) 二、编制依据 (2) 三、设计概况 (2) 1. GBF高分子（PP、PE）合金薄壁方箱简介 (2) 2、空心楼盖设计 (3) 四、施工准备及计划 (7) 1、技术准备 (7) 2、施工进度计划 (7) 3、材料与设备计划 (7) 4、劳动力计划 (8) 5、现场准备 (8) 五、施工工艺技术 (9) 2、工艺流程图 (9) 2、施工方法 (9) 3、注意事项 (11) 六、质疑保证措施 (14) 1、质量验收标准 (14) 2、质量管理体系 (18) 3、质量管理措施 (18) 七、安全保证措施 (20) 八、应急预案 (21) 1、应急组织机构及职责 (21) 2、危险源识别分析 (22) 3、安全事故应急流程 (22) 4、安全事故应急事故及处置 (23) 5、安全事故应急救援电话及定点医院 (24) 九、计算书及相关附件 (25) 2、计算书 (25) 2、相关附件 (25) PPE合金薄璧方箱进场记录表 (26) PPE合金薄璧方箱安装检验批质量验收记录表 (26)
XX项目空心楼盖施工方案 一、工程概况 盘项LI位于xx市xx路，总建筑面积xx m7,共x栋x建筑，地上x层，地下x层。2、空心楼盖部位 部位结构形式层咼板厚混凝土强度等级
一、工程概况 1.1 本工程结构为地上六层钢筋混凝土框架结构，室内外高差1.100M, 建筑物高度21.50M, 设计标高± 0.000 与绝对标高关系见总图。1.2 本工程结构设计使用年限为50 年，未经技术鉴定或设计许可，不得改变结构的用途和使用环境。 1.3 凡预留洞、埋件应严格按照结构图 二、编制依据 本工程 编制依据 1、Xx 设计院设计的xx 工程施工图（建施、结施、水施、电施） 2、施工合同书 3、图纸会审 4、《混凝土结构施工及验收规范》GB50204－92 5、《砖石工程施工及验收规范》GBJ203－83； 6、《屋面工程技术规范》JGJ73－91 7、《建筑地面工程施工及验收规范》GB50209－95 8、《建筑装饰工程施工及验收规范》JGJ73－91 9、《建筑安全技术规程》 10、《采暖与卫生工程施工及验收规范》GBJ242－82 11、《建筑电气安装工程质量检验评定标准》GBJ303－88 12、《建筑工程质量检验评定标准》GBJ301－88 13、其它现行国家有关施工及验收规范； 三、施工准备 （一）作业条件 1、办完验槽记录及地基验槽隐检手续。 2、办完基槽验线预检手续。 3、有砼配合比通知单、准备好试验用工器具。 4、做完技术交底。 （二）材质要求 1、水泥：水泥品种、强度等级应根据设计要求确定，质量符合现行水泥标准。工期紧时可做水泥快测。必要时要求厂家提供水泥含碱量的报告。 2、砂、石子：根据结构尺寸、钢筋密度、砼施工工艺、砼强度等级的要求确定石子粒径、砂子细度。砂、石质量符合现行标准。必要时做骨料碱活性试验。 3、水：自来水或不含有害物质的洁净水。 4、外加剂：根据施工组织设计要求，确定是否采用外加剂。外加剂必须经试验合格后，方可在工程上使用。 5、掺合料：根据施工组织设计要求，确定是否采用掺合料。质量符合现行标准。 6、钢筋：钢筋的级别、规格必须符合设计要求，质量符合现行标准要求。表面无老锈和油污。必要时做化学分析。 7、脱模剂：水质隔模剂。 （三）工器具备有搅拌机、磅秤、手推车或翻斗车、铁锹、振捣棒、刮杆、木抹子、胶皮手套、串桶或溜槽、钢筋加工机械、木制井 1、技术准备工作： （1）、组织有关人员熟悉工程设计图纸，了解设计意图对图纸中不明确的地方积极与设计单位进行联系，并进行图纸会审。 （2）、根据建设单位提供的《合肥市测绘设计研究院建设工程防线测量回执》。将本工程的定位桩用专用仪器引测至开挖 线以外，将开挖线用白灰撒出。 （3）、完善各种制度及资料，作好技术交底工作。 2、施工准备工作： （1）、在建设单位的协助下，解决好施工现场“三通一平”工作，安接水源、电源做好施工电缆线的敷设与临时设施的搭设工作。 （2）、及时采购各种施工用料。购置水泵及麻袋等基础施工过程中需要的各种机具、材料。 （3）、积极联系土方施工机械，合理选择机械队伍。组织钢筋加工等大型机械的进场工作。
福州温泉办公综合服务大楼工程GBF蜂巢芯现浇混凝土空心楼盖 施 工 技 术 方 案 编制单位：福州楼安建筑工程有限公司 二00七年九月
GBF蜂巢芯现浇混凝土空心楼盖施工技术方案 一、工程及技术概况： 福州温泉办公综合服务大楼工程位于福州市福州广场南侧，地面以上建筑层数为一十二层。该工程二层及以上的楼面板及屋面板均采用了长沙巨星轻质建材股份有限公司的专利GBF蜂巢芯现浇混凝土空心楼盖技术及其蜂巢芯单面外露模产品，其中A~B轴间GBF蜂巢板厚度为250mm，采用的蜂巢芯产品厚度为200 mm，B~C轴间GBF蜂巢板厚度为300 mm，采用的蜂巢芯产品厚度为250 mm，本工程GBF蜂巢芯现浇空心楼盖应用面积约为7420m2。GBF蜂巢芯现浇混凝土空心楼盖技术成果是建设部重点推广项目，已在全国二十多个省市的500多个工程中成功应用。GBF蜂巢芯现浇混凝土空心楼盖是一种由现浇混凝土框架暗梁（或明梁）、密肋梁、现浇板和置于肋间非拆除式蜂巢芯（单面外露模）组成的楼盖。根据柱网、板跨、荷载等的具体要求，由结构设计确定蜂巢芯的高度、蜂巢芯楼盖的总厚度、楼盖断面中孔间密肋及暗梁宽度（或明梁的宽度和高度）、梁板配筋等参数。暗梁、密肋与楼盖等厚，可设计成预应力或非预应力梁。GBF蜂巢芯现浇混凝土空心楼盖较普通框架梁板结构楼盖具有以下技术优势：○1实现大跨度，大开间，自重轻、隔音好、可灵活分隔的双向水平结构楼盖；○2节约水泥、混凝土、钢材和模板用量；○3加快施工进度约30%。蜂巢芯在现浇混凝土楼盖结构中应用时，不仅仅是一个空腔模构件，而且蜂巢芯底板可充作密肋间的吊顶，使密肋楼盖底部呈现出无梁板的效果，不仅很好解决了建筑的大跨度，大开间问题，且使建筑物具有自重轻、隔热、保温、隔音、空间可灵活间隔、双向受力传力相同、挠度变形小、抗剪抗扭性能好、抗震性好的优良性能。蜂巢芯密肋楼盖的房间无需吊顶，管线布设方便，模板施工简单方便，从而加快施工进度30％，降低主体结构工程综合造价3～8%，减少钢筋、水泥、模板高能耗材料5～15%，具有明显的经济效益和社会效益。蜂巢芯作为新型混凝土密肋楼盖结构非拆除式单面外露模材料，主要用于各类建筑物、构筑物、桥梁、港口码头等结构工程。 二、施工工艺流程：
混凝土框架柱涨模、偏位处理方案 现场混凝土浇筑完成后，发现部分框架柱出现涨模、偏位等现象，现结合现场情况及混凝土质量通病防治措施，对该部分框架柱进行处理。 一、钢筋混凝土框架柱涨模 （一）原因分析 1、管理因素： （1）这段时间施工任务紧张，一味盲目的追求进度，对质量管理有所松懈。 （2）管理人员在过程质量检查时，走马观花、敷衍了事，缺乏责任心。 （3）对质量管理中的质量验收程序执行不彻底。 2、技术因素 （1）模板支设时未按照或未完全按照既定施工方案进行施工。 （2）混凝土浇筑时分层厚度过大、过振。 （二）处理措施 1、管理措施 （1）在思想上加强所有施工参建人员的意识，是每个人时时刻刻都牢记施工质量控制是进度控制、成本控制的前提。 （2）加强管理人员在过程检查时的责任心，切实的履行自己岗位职责。采取经济奖惩措施，功必奖过必罚。 （3）整顿并坚持报验程序，坚持自检、互检及交接检的三检制度。三检完后按程序进行报验，严禁未经报验程序进入下道工序。 2、技术措施 （1）技术人员重新对施工专项方案进行审核，结合工程中出现的质量问题改进施工方案和施工工艺，重新制定最适合本工程特点施工方案和施工工艺。 （2）组织施工人员学习施工方案及操作工艺，使每个管理人员及每一个操作工人熟练掌握每一个操作步骤和每一个操作细节，做到人人心中有数。 （三）施工措施 1、施工准备 （1）计划修补的柱子采用标记法进行标注清楚，并采用墨线把涨模部分弹出，核对是否正确，并有核对记录。 （2）对施工过程中使用的架子、锤子、铁锤、吊锤、墨斗准备好。
（3）对操作施工人员进行施工技术、安全的交底。 （4）要求待修补处的砼强度达到设计强度的90％后，才能进行修补工作。 2、施工工艺 标注框架柱涨模部分→涨模部分弹线→剔凿涨模部分→清扫松散部分混凝土→浇水湿润→对局部进行水泥砂浆拉毛 3、施工要点 （1）先弹垂直线，将涨模一侧混凝土面用钢钎逐层剔凿，用毛刷刷干净，并用水冲洗，使其无松动石子及粉尘。 （2）检查因涨模是否引起钢筋位移。如果钢筋位移，剔凿的深度应满足钢筋复位后保护层厚度要求，然后进行钢筋复位。重新用毛刷刷干净，并用水冲洗，使其无松动石子及粉尘。 （3）对修补处涂刷一层用同结构砼相同的水泥做成水泥浆进行界面处理，以使新旧混凝土能结合良好。 （4）用1：2或1:2.5水泥砂浆进行抹面处理。如果厚度超过20mm，需挂设钢丝网进行补强处理。施工完毕终凝后加强淋水养护。 （5）对于凿除的混凝土垃圾应及时进行清理干净，并运到室外垃圾场。 二钢筋混凝土框架柱偏位 （一）原因分析 1、经过轴线测量放线，检查发现部分框架柱的纵向受力钢筋存在偏移的现象。钢筋质量问题产生原因分析：钢筋绑扎不到位及浇捣砼时钢筋受冲击偏移。 （二）处理措施 1、钢筋位移不大于20mm： 如果钢筋位移在20mm范围内，可剔凿钢筋根部的混凝土，深度约6～8厘米，然后用扳手将钢筋调整到位，保证模板支设即可。这样的处理，符合钢筋≥1：6改变位置的要求。按照≥1：6的比例调整钢筋概念：如果钢筋位移了20mm，在顶板以上不小于20×6=120mm 的高度范围内调整到位。禁止采用热处理的方式，将钢筋煨弯。 2、钢筋位移在20mm至40mm之间： 如果钢筋位移在20mm到40mm之间，同样将钢筋根部的混凝土剔凿约8厘米深度，然后用扳手将钢筋调整到位，保证模板支设，同时采取钢筋根部绑扎钢筋的方法进行加固，加筋的直径同原结构钢筋，加筋需要与打弯的钢筋绑扎搭接在一起。
商业楼（自编柯木塱销售展览中心及配 套实施） GBF蜂巢芯现浇混凝土空心楼盖 施 工 技 术 方 案 编制单位：广西五建 2017年9月
GBF蜂巢芯现浇混凝土空心楼盖施工技 术方案 一、工程及技术概况： 商业楼（自编：柯木塱销售展览中心及配套设施）项目位于广州市天河区广汕一路背坪村旁，地面以上4层（局部5层）。该工程二层以上，均为GBF蜂巢芯现浇混凝土空心楼板结构。其中GBF蜂巢芯现浇楼板厚为400，采用蜂巢芯预制块的主规格为：900*900*350，配套规格为900*600*350、600*600*350、900*300*350。GBF蜂巢芯现浇混凝土空心楼盖是一种由现浇混凝土框架暗梁（或明梁）、密肋梁、现浇板和置于肋间非拆除式蜂巢芯（单面外露模）组成的楼盖。根据柱网、板跨、荷载等的具体要求，由结构设计确定蜂巢芯的高度、蜂巢芯楼盖的总厚度、楼盖断面中孔间密肋及暗梁宽度（或明梁的宽度和高度）、梁板配筋等参数。暗梁、密肋与楼盖等厚，可设计成预应力或非预应力梁。GBF蜂巢芯现浇混凝土空心楼盖较普通框架梁板结构楼盖具有以下技术优势：○1实现大跨度，大开间，自重轻、隔音好、可灵活分隔的双向水平结构楼盖；○2节约水泥、混凝土、钢材和模板用量；○3加快施工进度约30%。蜂巢芯在现浇混凝土楼盖结构中应用时，不仅仅是一个空腔模构件，而且蜂巢芯底板可充作密肋间的吊顶，使密肋楼盖底部呈现出无梁板的效果，不仅很好解决了建筑的大跨度，大开间问题，且使建筑物具有自重轻、隔热、保温、隔音、空间可灵活间隔、双向受力传力相同、挠度变形小、抗剪抗扭性能好、抗震性好的优良性能。蜂巢芯密肋楼盖的房间无需吊顶，管线布设方便，模板施工简单方便，从而加快施工进度30％，降低主体结构工程综合造价3～8%，减少钢筋、水泥、模板高能耗材料5～15%，具有明显的经济效益和社会效益。蜂巢芯作为新型混凝土密肋楼盖结构非拆除式单面外露模材料，主要用于各类建筑物、构筑物、桥梁、港口码头等结构工程。
框架柱混凝土专项施工方案 一.承重支架的搭设 钢管支架是在外墙安全防护脚手架的基础上形成一个三排全钢脚手架体系，由于柱子较高，框架梁离天面10米，因此，在脚手架安装时，应严格按照脚手架安装规范进行安装。其方案详见脚手架专项施工方案。 二.模板的制作和安装 1. 模板的作用和要求：模板是使混凝土构件按设计图几何尺寸成型的模型板。在施工过程中还要求模板能承受模板的自重，钢筋和混凝土的重量，运输工具，施工人员活荷重和混凝土对侧板的压力及振捣机械的动力作用。要求模板和支撑架必须达到以下几点要求： （1）保证结构和构件各部分形状尺寸和相互位置的正确性， （2）具有足够的强度，刚度和稳定性。 （3）构件简单，便于钢筋绑扎，混凝土浇筑和养护的要求。 （4）模板接缝要严密，不得漏浆。 （5）要选材合理，用料经济。 2.模板选料及制作 （1）.本工程钢筋混凝土框架柱选用拼合式模板，采用18mm 厚九夹板，50*70方木和40mm 梁底等材料组成框架柱梁模板。为了保证末班符合要求，便于模板制作安装和拆卸，应该做好放
样工作，这不仅对结构的质量有直接的影响，而且对节约人力物力都有重要意义。 （2）. 根据放样图即可制作模板，在制作过程中必须考虑到模板的作用和要求等因素，结合材料规格，加工技术水平，力求省工，省料。 （3）. 考虑柱梁模拼接拼装方法，加钉部位及数量，达到制模方便，安装简便，拆模方便。 3.模板安装 模板安装顺序：测量轴线和标高——安装柱模板——调整柱模板的垂直度——加固柱模板——安装大梁底板——侧板——检查轴线偏差——加固梁模板 三.钢筋的制作与安装 1. 本工程钢筋用量大，规格多，为提高钢筋制作效率，施工程序如下：熟悉配筋图——配料——断料——成型——吊运就位——柱梁筋绑扎——箍筋绑架——验收 2.钢筋工程质量要点 （1）. 所有钢筋进场必须有产品合格证和试验报告，钢筋的规格，间距根数必须符合设计要求。 （2）.定期对钢筋班组进行技术交底工作。 （3）. 钢筋的交叉点要用钢丝绑扎牢固，不得有松动和位移现象，箍筋绑扎时应与主筋垂直。
GBF蜂巢芯现浇混凝土密肋楼盖在建筑工程中的应用 摘要：结合山东友邦置业有限公司开发的地下车库工程，详细介绍了GBF蜂巢芯现浇混凝土密肋楼盖的设计原理、施工工艺流程以及施工中应控制的几个施工要点。 关键词：GBF蜂巢芯；密肋楼盖；设计原理；施工流程；施工要点 GBF蜂巢芯现浇混凝土密肋楼盖概述 GBF蜂巢芯是一种高强的薄壁复合材料芯盒，其结构似蜂窝，是由高强度的水泥砂浆和玻璃纤维通过大型设备压制而成，空腔封闭。其最大优点是：结构好，重量轻，造价低，施工速度快。 GBF蜂巢芯现浇混凝土密肋楼盖是采用GBF蜂巢芯作为填充内模与现浇混凝土整体浇筑，形成具有大空腔效果的一种楼盖形式。具有完全现浇、T型受力断面、底部平整、大空腔构造、空间受力的特征，基本受力单元是“T”型双向密肋梁。 GBF蜂巢芯是混凝土预制构件，简称芯模。是蜂巢芯密肋楼盖的重要组成部分与技术核心。GBF蜂巢芯作为密肋楼盖的填充内模，同时作为双向现浇肋梁的侧模，其设计与施工必须按照施工图纸结合正规厂家提供的施工工法进行。 1 工程实例 由中铁三局集团第四工程有限公司承建的山东友邦置业开发的易安明郡工程一期地下车库楼盖结构采用的是GBF蜂巢芯现浇混凝土密肋楼盖技术。 本工程根据场地的地势特点为南高北低，故设计地下车库地面不为一平。为便于绘图、识图，本基础图根据车库地面标高不同分为五个区，各分区详车库分区平面图，本车库按选用住宅11#楼一层地面标高为±0.000，±0.000绝对标高为186.300。本工程采用独立基础加防水板及墙下条基，持力层选用第3层碎石和第4层微风化石灰岩，局部超挖清除第2层黄土及第3层碎石，采用C15毛石混凝土进行换填至基底标高。第3层碎石，地基承载力特征值为 fak=300Kpa；第4层微风化石灰岩，地基承载力特征值为 fak=3500Kpa。本工程为山地地基，基岩分布复杂，在验槽过程中，根据实际情况由勘察单位判定基底标高的持力层和设计完全一致后方可施工。 为有效减轻地基上部建筑物的自重，获得良好的建筑隔音效果，提高其适用性，在该工程楼板施工中采用了GBF蜂巢芯现浇混凝土密肋楼盖施工技术。
柱下钢筋混凝土独立基础设计任务书 （一）设计题目 某教学楼为四层钢筋混凝土框架结构，柱下独立基础，柱网布置如图所示， 试设计该基础。 （二）设计资料 ⑴工程地质条件 该地区地势平坦，无相邻建筑物，经地质勘察：持力层为粘性土，土的天然 3 2 重度为18 kN/m ，地基承载力特征值f ak=230kN/m ，地下水位在-6.3m 处。相关数据可查阅规范。 ⑵给定参数 柱截面尺寸为450mm×450mm，在基础顶面处的相应于荷载效应标准组合，荷载由上部结构传来有以下五种情况： ①单柱轴心荷载为900kN，弯矩值为100kN·m，水平荷载为20kN。 ②单柱轴心荷载为850kN，弯矩值为80kN·m，水平荷载为15kN。 ③单柱轴心荷载为850kN，弯矩值为90kN·m，水平荷载为15kN。
④单柱轴心荷载为800kN，弯矩值为70kN·m，水平荷载为10kN。 ⑤单柱轴心荷载为800kN，弯矩值为50kN·m，水平荷载为10kN。 ⑶材料选用 2 混凝土：采用C20（可以调整）（f t=1.1N/mm ）； 2 钢筋：采用HRB335（可以调整）（f y=210 N/mm ）。 （三）设计内容(只需设计一个独立基础) ⑴定基础埋置深度； ⑵定地基承载力特征值； ⑶确定基础的底面尺寸； ⑷确定基础的高度； ⑸基础底板配筋计算； ⑹绘制施工图（平面图、详图）。 （四）设计要求 ⑴计算书要求书写工整、数字准确、图文并茂。 ⑵制图要求所有图线、图例尺寸和标注方法均应符合新的制图标准，图纸 上所有汉字和数字均应书写端正、排列整齐、笔画清晰，中文书写为仿宋字。 （五）设计成果要求 课程设计结束各位同学须按时提交以下成果并统一用档案袋装好： ⑴设计任务书一份； ⑵设计计算书一份； ⑶基础设计施工图纸一张（A1#图纸）图纸应该包括：基础平面布置图、基础配筋图、基础配筋详图以及相应的剖面图等。 （六）具体各组设计任务如下：(2~3 人一组) 第一组：设计第①种荷载下的柱下独立基础； 第二组：设计第②种荷载下的柱下独立基础； 第三组：设计第③种荷载下的柱下独立基础； 第四组：设计第④种荷载下的柱下独立基础； 第五组：设计第⑤种荷载下的柱下独立基础。 2
钢筋混凝土结构中短柱的成因及防治 钢筋混凝土结构中短柱的成因及防治 摘要：为保证短柱结构的安全, 在设计施工中应严格执行国家建筑抗震设计规范, 采取切实可行的构造措施, 防止短柱破坏, 在 施工中遇到用户提出修改设计出现短柱问题时, 应及时进行妥善处理, 有针对性地采取措施, 保证结构安全。本文探讨了钢筋混凝土结构中短柱的成因及防治。 关键词：钢筋混凝土；结构；短柱；成因；防治 中图分类号：TU37 文献标识码：A 文章编号： 在多层及高层钢筋混凝土框架结构中，经常会出现短柱，甚至是极短柱。在建筑物遭受本地区设防烈度或高于本地区设防烈度的地震时，短柱很容易发生剪切破坏而造成主体结构破坏，甚至倒塌，违反了“小震不坏，中震可修，大震不倒”的三水准设防要求。因此，为了避免短柱发生脆性破坏，要提高短柱的延性和抗震性能。 一、短柱的定义 钢筋混凝土框架的短柱是指柱的净高与截面长边尺寸之比小于4的柱, 即H 0: h0 < 4 (H 0 为层间柱的净高, h0为柱截面有效高度)。抗震规范中是用剪跨比K来定义短柱K= M /Vh0, 1. 5 < K[ 2. 0时为短柱, K[ 1. 5时为极短柱, (式中:M 为柱端截面组合的弯矩计算值; V为对应的截面组合剪力计算值)。长柱一般发生弯曲破坏; 短柱多数发生剪切破坏; 极短柱发生剪切斜拉破坏。短柱的剪切破坏属于脆性破坏。在实际工程中出现短柱的原因有2大类, 一是工程设计中的问题, 二是施工中改变原设计。 二、钢筋混凝土结构中短柱的成因 钢筋混凝土框架的短柱是指柱的剪跨比小于4 的柱, 即H o/ ho < 4 (H o为层间柱的净高,ho 为柱截面的高) 。短柱的破坏状态为脆性破坏。 在实际工程中出现短柱的原因可分为两大类, 一是工程设计中
前言 随着社会的发展，钢筋混凝土框架结构的建筑物越来越普遍。由于钢筋混凝土结构与砌体结构相比较具有承载力大、结构自重轻、抗震性能好、建造的工业化程度高等优点；与钢结构相比又具有造价低、材料来源广泛、耐火性好、结构刚度大、使用维修费用低等优点。因此，在我国钢筋混凝土结构是多层框架最常用的结构型式。近年来，世界各地的钢筋混凝土多层框架结构的发展很快，应用很多。一般框架结构是由楼板、梁、柱及基础4种承重构件组成的，由主梁、柱与基础构成平面框架，各平面框架再由连续梁连接起来而形成的空间结构体系。在合理的高度和层数的情况下，框架结构能够提供较大的建筑空间，其平面布置比较的灵活，可适合多种工艺与使用功能的要求。下面介绍下框架结构的基本信息及一些常见的问题[1]。 1.文献综述正文 钢筋混凝土框架结构是由楼板、梁、柱及基础四种承重构件组成的。由主梁、柱与基础构成平面框架，各平面框架再由连续梁连接起来形成空间结构体系。高层建筑采用框架结构体系时，框架梁应纵横向布置，形成双向抗侧力构件，使之具有较强的空间整体性，以承受任意方向的侧向力。框架结构具有建筑平面布置灵活、造型活泼等优点，可以形成较大的使用空间，易于满足多功能的使用要求。在结构受力性能方面，框架结构属于柔性结构，自振周期较长，地震反应较小，经过合理的结构设计，可以具有较好的延性性能[2]。其缺点就是整体侧向刚度较小，在强烈地震作用下侧向变形较大，容易使填充墙产生裂缝，并引起建筑装修、玻璃幕墙等非结构构件的破坏。不仅地震中危及人身安全和财产损失，而且震后的修复工作和费用也很大[3]。同时当建筑层数较多或荷载较大时，要求框架柱截面尺寸较大，既减少了建筑使用面积，又会给室内办公用品或家具的布置带来不便，因此这种结构一般用于非地震区或层数较少的低烈度高层建筑。另外框架结构的承载力较低，它的受力特点类似于竖向悬臂剪切梁，楼层越高，水平位移越慢，高层框架在纵横两个方向都承受很大的水平力，这时，现浇楼面也作为梁共同工作的构件，装配整体式楼面的作用则不考虑，框架结构的墙体是填充墙，起围护和分隔作用。
安全告知 为便于安装，蜂巢芯箱体顶端中间位置设有吊装环，为防止在吊装过程中箱体出现脱钩现象，吊装环部位严禁打凿。为保证施工安全，正在吊装作业的蜂巢芯箱体下方禁止有人通行或停留！吊装蜂巢芯应遵守《塔式起重机操作使用规程》（JG-T100 —1999）之规定。 安装固定蜂巢芯过程中，应在盒顶及肋梁上部铺设操作马道（如铺垫木板作保护），不允许施工人员直接踩踏蜂巢芯（以预防施工人员踏空或摔倒等安全隐患）。 蜂巢芯安装技术交底记录 工程名称： 建设单位： 交底单位： 交底人： 交底接受单位: 接受人：
现浇混凝土GBF蜂巢芯密肋楼盖施工工法 第一章总则 第1.0.1条为了在施工中正确贯彻现浇混凝土GBF蜂巢芯密肋楼盖的设计意图与技术要求，保证工程质量，针对该技术的关键环节制定本施工工法。 第1.0.2条本施工工法适用于建筑施工现场进行以GBF蜂巢芯作非拆除式肋间模壳的现浇混凝土密肋楼盖施工和质量验收。 第1.0.3条本施工工法根据本技术专利权人长沙巨星轻质建材股份有限公司的研究、试验、大量应用资料，并依据国家现行有关法规、标准和规程而编制。 第1.0.4条在按本施工工法进行施工操作与检查时，除应符合本篇条文规定外，尚应遵从国家现 行有关建筑施工的标准、规范、规程。 第二章主要技术特点与施工工艺流程 第2.0.1条现浇混凝土GBF蜂巢芯密肋楼盖是一种由现浇混凝土框架暗梁（或明梁）、密肋梁、板和非拆除式肋间单面外露模壳组成的楼盖。 第2.0.2条根据柱网、板跨、荷载等的具体要求，由结构设计确定蜂巢芯的高度、蜂巢芯楼盖的总厚度、楼盖断面中孔间密肋及暗梁宽度（或明梁的宽度和高度）、梁板配筋等参数。 第2.0.3条暗梁与楼盖等厚，可设计成预应力或非预应力梁。 第2.0.4条现浇混凝土蜂巢芯密肋楼盖的施工工艺流程见图1。
钢筋混凝土底板、墙的钢筋施工工艺标准 1 材料及主要机具： 1.1 钢筋：应有出厂合格证，按规定作力学性能复试。当加工过程中发生脆断等特殊情况，还需作化学成分检验。钢筋应无老锈及油污。 1.2 铁丝：可采用20～22号铁丝（火烧丝）或镀锌铁丝（铅丝）。铁丝的切断长度要满足使用要求。 1.3 控制混凝土保护层用的砂浆垫块、塑料卡、各种挂钩或撑杆等。 1.4 工具：钢筋钩子、撬棍、扳子、绑扎架、钢丝刷子、手推车、粉笔、尺子等。 2 作业条件： 2.1 按施工现场平面图规定的位置，将钢筋堆放场地进行清理、平整。准备好垫木，按钢筋绑扎顺序分类堆放，并将锈蚀进行清理。 2.2 核对钢筋的级别，型号、形状、尺寸及数量是否与设计图纸及加工配料单相同。 2.3 当施工现场地下水位较高时，必须有排水及降水措施。 2.4 熟悉图纸，确定钢筋穿插就位顺序，并与有关工种作好配合工作，如支模、管线、防水施工与绑扎钢筋的关系，确定施工方法，作好技术交底工作。 3 工艺流程： 划钢筋位置线→运钢筋到使用部位→绑底板钢筋→绑墙钢筋 3.1 划钢筋位置线：按图纸标明的钢筋间距，算出底板实际需用的钢筋根数，一般让靠近底板模板边的那根钢筋离模板边为5cm，在底板上弹出钢筋位置线（包括基础梁钢筋位置线）。 3.2 绑基础底板及基础梁钢筋 3.2.l 按弹出的钢筋位置线，先铺底板下层钢筋。根据底板受力情况，决定下层钢筋哪个方向钢筋在下面，一般情况下先铺短向钢筋，再铺长向钢筋。 3.2.2 钢筋绑扎时，靠近外围两行的相交点每点都绑扎，中间部分的相交点可相隔交错绑扎，双向受力的钢筋必须将钢筋交叉点全部绑扎。如采用一面顺扣应交错变换方向，也可采用八字扣，但必须保证钢筋不位移。 3.2.3 摆放底板混凝土保护层用砂浆垫块，垫块厚度等于保护层厚度，按每1m左右距离梅花型摆放。如基础底板较厚或基础梁及底板用钢量较大，摆放距离可缩小，甚至砂浆垫块可改用铁块代替。 3.2.4 底板如有基础梁，可分段绑扎成型，然后安装就位，或根据梁位置线就地绑扎成型。