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关于镇江西津渡的英语作文全文共3篇示例，供读者参考篇1A Glimpse into Zhenjiang's Xijindu: Where History and Nature ConvergeAs a student hailing from the ancient city of Zhenjiang, I find myself drawn to the captivating allure of Xijindu, a place where the threads of history intertwine with the breathtaking beauty of nature. Nestled along the banks of the mighty Yangtze River, this historic site has woven itself into the tapestry of my hometown, beckoning visitors to embark on a journey through time and immerse themselves in the rich cultural heritage that defines Zhenjiang.Xijindu, or the "Western Ferry Crossing," has long been a strategic gateway, serving as a vital transportation hub connecting the northern and southern regions of China. Its name pays homage to the ferries that once plied the waters, transporting people, goods, and ideas across the Yangtze's powerful currents. As I stand on the riverbank, gazing out at theexpanse of water, I am struck by the sense of awe and reverence that this place instills.The beating heart of Xijindu lies within the ancient ferry buildings that have withstood the test of time. These structures, adorned with intricate carvings and intricate architectural details, transport me back to an era when travelers would gather, eagerly awaiting their turn to cross the river. The very stones seem to whisper tales of merchants, scholars, and adventurers who passed through these halls, their footsteps echoing the rhythms of a bygone age.Yet, Xijindu is not merely a relic of the past; it is a living, breathing embodiment of Zhenjiang's enduring spirit. As I wander through the meticulously preserved ferry buildings, I am struck by the harmonious blend of history and modernity. Interactive exhibits and multimedia displays bring the stories of the past to life, allowing me to delve deeper into the rich tapestry of Zhenjiang's cultural heritage.Beyond the historical treasures, Xijindu offers a sanctuary for nature lovers like myself. The verdant greenery that surrounds the site provides a welcome respite from the bustle of city life. Strolling along the winding paths, I am enveloped by the soothing sounds of rustling leaves and the gentle whispers of thebreeze. It is here that I find solace, allowing my mind to wander and my soul to reconnect with the natural world.One of my favorite spots within Xijindu is the serene Gushan Garden, a verdant oasis that pays homage to the timeless art of Chinese landscaping. Meticulously manicured gardens, dotted with pavilions and ponds, invite visitors to slow down and appreciate the subtle beauty that surrounds them. As I meander along the winding paths, I am struck by the harmonious interplay of rockeries, streams, and carefully curated flora, each element a testament to the enduring wisdom of ancient Chinese gardeners.Yet, Xijindu is not merely a place of tranquility; it is a living canvas where culture and tradition are celebrated with fervor. During traditional festivals, the area comes alive with the vibrant colors of performers adorned in intricate costumes, reenacting ancient rituals and customs that have been passed down through generations. The air is filled with the melodic strains of traditional music, and the scent of incense wafts through the crowds, infusing the atmosphere with a sense of reverence and wonder.As a student, Xijindu holds a special place in my heart, for it is here that I have forged lasting memories and gained a deeper appreciation for the rich tapestry of my hometown. Whether it isstudying beneath the shade of ancient trees or engaging in thoughtful discussions with fellow students amidst the historical surroundings, Xijindu has become a sanctuary for learning and personal growth.In the end, Xijindu is a testament to the enduring spirit of Zhenjiang, a place where the past and present converge in perfect harmony. As I continue my journey through life, I carry with me the indelible imprints of this extraordinary place, a constant reminder of the profound beauty that can be found in the marriage of history and nature. It is my hope that future generations will cherish and preserve this gem, ensuring that the echoes of Xijindu's storied past continue to resonate for centuries to come.篇2A Journey Through Xijindu, the Historic Heart of ZhenjiangAs a student hailing from the ancient city of Zhenjiang, a place steeped in rich history and cultural heritage, I am constantly in awe of the wonders that my hometown has to offer. Among the many captivating sites that grace this city, none quite captures the essence of Zhenjiang's storied past like the Xijindu area.Nestled along the banks of the mighty Yangtze River, Xijindu has stood as a testament to the city's resilience and adaptability for centuries. This historic district, with its winding alleys, ancient temples, and preserved architectural marvels, offers a glimpse into the vibrant tapestry of Zhenjiang's past, intricately woven with threads of commerce, religion, and tradition.My journey through Xijindu begins at the iconic Beigu Wharf, where the rhythmic lapping of the Yangtze's waters against the stone embankment sets the stage for an immersive experience. This wharf, which dates back to the Tang Dynasty, has borne witness to countless ships and merchants, their sails billowing with the promise of trade and prosperity. As I stand on the very spot where countless travelers have embarked on their voyages, I am humbled by the weight of history that permeates the air.Wandering through the labyrinth of narrow streets, I am transported back in time, surrounded by the echoes of a bygone era. The Zhenghuangmiao Temple, a magnificent structure adorned with intricate carvings and vibrant hues, stands as a testament to the enduring spirituality of the region. Its towering gates and serene courtyards invite visitors to pause and reflect on the profound beliefs that have shaped the fabric of Zhenjiang's society.Nearby, the Laomendong Historical and Cultural Relic Street beckons, offering a tantalizing glimpse into the daily lives of Zhenjiang's residents throughout the ages. Here, I lose myself in a tapestry of sights, sounds, and aromas that transport me across centuries. Artisans skillfully craft traditional handicrafts, their nimble fingers deftly weaving intricate patterns into silken fabrics or molding clay into exquisite ceramics. The aroma of freshly brewed tea wafts through the air, mingling with the tantalizing scents of street food vendors, whose recipes have been passed down through generations.As I meander through the winding alleys, I am struck by the seamless integration of the old and the new. Centuries-old buildings stand side by side with modern structures, creating a harmonious fusion that pays homage to Zhenjiang's rich heritage while embracing its evolution. Each turn reveals a new surprise, from hidden courtyards adorned with meticulously pruned bonsai trees to quaint teahouses where locals gather to share stories and sip fragrant brews.One of the highlights of my journey is the Jiaoshan Garden, a breathtaking oasis of tranquility nestled within the heart of Xijindu. This exquisite garden, dating back to the Qing Dynasty, showcases the profound reverence for nature that has long beeningrained in Zhenjiang's culture. Carefully manicured landscapes, meticulously crafted rock formations, and serene ponds adorned with graceful bridges create a harmonious symphony of natural beauty and human artistry.As I stroll along the winding paths, surrounded by the gentle rustling of bamboo groves and the melodic trickle of streams, I am reminded of the timeless wisdom embodied in the principles of feng shui. Each element, from the placement of rocks to the orientation of structures, is thoughtfully arranged to foster a sense of balance and harmony, inviting visitors to connect with the rhythms of nature and find inner peace.Throughout my exploration of Xijindu, I am struck by the enduring spirit of resilience that permeates every corner of this historic district. Despite the ravages of time, war, and natural disasters, the people of Zhenjiang have remained steadfast in their commitment to preserving and celebrating their cultural heritage. Each meticulously restored building, each lovingly tended garden, and each cherished tradition speaks to the unwavering determination of a city that has weathered countless storms yet emerged even stronger, its roots firmly planted in the fertile soil of its storied past.As the sun begins to dip below the horizon, casting a warm, golden glow over the ancient rooftops and winding alleyways, I pause to reflect on the profound lessons that Xijindu has imparted. This historic district is not merely a relic of the past; it is a living, breathing testament to the enduring power of human ingenuity, perseverance, and cultural pride.In a world that often moves at a dizzying pace, Xijindu stands as a sanctuary, a place where time seems to slow down, inviting visitors to immerse themselves in the rich tapestry of Zhenjiang's history. With each step, I am reminded of the importance of cherishing our roots, honoring our traditions, and embracing the wisdom of those who came before us.As I bid farewell to the winding streets and ancient courtyards, I carry with me a renewed sense of appreciation for the invaluable treasures that Xijindu holds. This historic district is not merely a destination; it is a living embodiment of Zhenjiang's spirit, a testament to the enduring legacy of a city that has withstood the test of time and emerged as a shining beacon of cultural pride and resilience.篇3The Winding Waters of History: Exploring Zhenjiang's Western Zither CrossingAs a student of history, I have always been captivated by the tales woven into the fabric of ancient cities, where every stone whispers secrets of bygone eras. Among the myriad wonders that dot the landscape of Zhenjiang, a city renowned for its rich cultural tapestry, one site stands out as a testament to the indomitable human spirit – the Western Zither Crossing.Nestled along the meandering Yangtze River, this historic ferry crossing has borne witness to the ebb and flow of civilizations, serving as a vital link between the northern and southern realms of ancient China. Its name, derived from the zither-like shape of the river's contours, evokes a melodious symphony that echoes through the annals of time.To truly appreciate the significance of the Western Zither Crossing, one must delve into the annals of Zhenjiang's storied past. This city, once known as Zhengjiang, rose to prominence during the Tang Dynasty, a golden age of cultural efflorescence and economic prosperity. As trade flourished along the Yangtze, the need for a reliable means of traversing its mighty waters became paramount.It was here, amidst the rushing currents, that the ingenuity of ancient engineers took flight. Employing a system of intricate pulleys and ropes, they constructed a ferry system that defied the river's relentless flow. Imagine the awe that must have filled the hearts of travelers as they watched their vessels glide across the water, propelled not by oars or sails, but by the sheer force of human determination.Yet, the Western Zither Crossing was more than a mere transportation hub; it was a crucible of cultural exchange, where ideas, goods, and stories intermingled like the waters themselves. Merchants from far-flung lands would gather, trading not only wares but also tales of their journeys, weaving a tapestry of diverse perspectives that enriched the intellectual landscape of Zhenjiang.As I stand on the banks of the Yangtze, gazing upon the remnants of this ancient crossing, I cannot help but imagine the myriad narratives that have unfolded here. I envision the processions of imperial envoys, their silken robes billowing in the wind, as they embarked on diplomatic missions that would shape the course of empires. I picture the weary travelers, their backs laden with the spoils of distant lands, seeking refuge and respite at the inns that once lined the riverbanks.But the Western Zither Crossing is not merely a relic of the past; it is a living, breathing testament to the resilience of human ingenuity. Even as modernity has ushered in new modes of transportation, this ancient crossing remains a symbol of our ancestors' determination to conquer the obstacles that nature placed before them.As I wander through the narrow alleyways that wind their way around the crossing, I am struck by the seamless fusion of past and present. Centuries-old temples stand in quiet reverence, their intricate carvings and vibrant frescoes a reminder of the artistic mastery of bygone eras. Yet, just a stone's throw away, modern cafes and boutiques beckon, offering a tantalizing glimpse into the ever-evolving tapestry of Zhenjiang's cultural landscape.It is this juxtaposition of ancient and modern, of tradition and innovation, that truly captivates me. For in the Western Zither Crossing, I see a microcosm of humanity's enduring quest for knowledge, exploration, and connection. It is a testament to our ability to adapt, to overcome, and to forge enduring bonds that transcend the boundaries of time and space.As I bid farewell to this extraordinary site, I carry with me a renewed sense of appreciation for the rich tapestry of historythat surrounds us. The Western Zither Crossing serves as a powerful reminder that our present is inextricably linked to our past, and that by understanding the triumphs and struggles of those who came before us, we can better navigate the challenges that lie ahead.In the winding waters of the Yangtze, I have discovered a wellspring of inspiration, a testament to the indomitable human spirit that has endured through the ages. And as I embark on my own journey through the realms of knowledge, I carry with me the lessons of the Western Zither Crossing – to embrace curiosity, to persevere in the face of adversity, and to forever seek the connections that bind us all together.。
两种生物基聚氨酯密封胶通过美国农业部认证
佚名
【期刊名称】《粘接》
【年(卷),期】2011(32)9
【摘要】本刊讯日前，两种高密度生物基聚氨酯密封胶已获得美国农业部认证，贴上了生物基产品的标签。
这意味着产品符合美国农业部BioPreferredTM体系的生物基标产品标准。
【总页数】1页(P25-25)
【关键词】聚氨酯密封胶;美国农业部;生物;认证;产品标准;高密度
【正文语种】中文
【中图分类】TQ433.432
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CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2017年第36卷第5期·1658·化 工 进展乙酸蒸汽催化重整制氢的研究进展王东旭1，肖显斌2，李文艳1（1华北电力大学能源动力与机械工程学院，北京 102206；2华北电力大学生物质发电成套设备国家工程实验室，北京 102206）摘要：通过生物油蒸汽重整制备氢气可以减少环境污染，降低对化石燃料的依赖，是一种极具潜力的制氢途径。
乙酸是生物油的主要成分之一，常作为模型化合物进行研究。
镍基催化剂是乙酸蒸汽重整过程中常用的催化剂，但容易因积炭失去活性，降低了制氢过程的经济性。
本文首先分析了影响乙酸蒸汽重整制氢过程的各种因素，阐述了在这一过程中镍基催化剂的积炭原理，讨论了优化镍基催化剂的方法，包括优化催化剂的预处理过程、添加助剂和选择合适的载体，最后对乙酸蒸汽重整制氢的热力学分析研究进展进行了总结。
未来应重点研究多种助剂复合使用时对镍基催化剂积炭与活性的影响，分析多种助剂的协同作用机理，得到一种高活性、高抗积炭能力的用于生物油蒸汽重整制氢的镍基催化剂。
关键词：生物油；乙酸；制氢；催化剂；热力学中图分类号：TK6 文献标志码：A 文章编号：1000–6613（2017）05–1658–08 DOI ：10.16085/j.issn.1000-6613.2017.05.014A review of literatures on catalytic steam reforming of acetic acid forhydrogen productionWANG Dongxu 1，XIAO Xianbin 2，LI Wenyan 1（1 School of Energy ，Power and Mechanical Engineering ，North China Electric Power University ，Beijing 102206，China ；2 National Engineering Laboratory for Biomass Power Generation Equipment ，North China Electric PowerUniversity ，Beijing 102206，China ）Abstract ：Hydrogen production via steam reforming of bio-oil ，a potential way to produce hydrogen ， can reduce environmental pollution and dependence on fossil fuels. Acetic acid is one of the main components of bio-oil and is often selected as a model compound. Nickel-based catalyst is widely used in the steam reforming of acetic acid ，but it deactivates fast due to the carbon deposition. In this paper ，the affecting factors for the steam reforming of acetic acid are analyzed. The coking mechanism of nickel-based catalyst in this process is illustrated. Optimization methods for nickel-baed catalyst are discussed ，including optimizing the pretreatment process ，adding promoters ，and choosing appropriate catalyst supports. Research progresses in the thermodynamics analyses for steaming reforming of acetic acid are summarized. Further studies should be focused on the effects of a combination of a variety of promoters on carbon deposition. Catalytic activity and the synergy mechanism should be analyzed to produce a novel nickel-based catalyst with high activity ，high resistance to caborn deposition for hydrogen production via steam reforming of bio-oil. Key words ：bio-oil ；acetic acid ；hydrogen production ；catalyst ；thermodynamics第一作者：王东旭（1994—），男，硕士研究生，从事生物质能利用技术研究。
国外安全文献综述与实践（正文）目录1.课题分析 (1)2.检索策略 (1)2.1选择检索工具 (1)2.2选择检索词 (1)2.3拟定检索式 (1)3.检索步骤以及检索结果与评价 (2)3.1学术期刊全文库 (2)3.1.1检索式 (2)3.1.2检索步骤与结果 (2)3.2 谷歌搜索引擎 (5)3.2.1检索式 (5)3.2.2检索步骤及检索结果 (5)3.3百度搜索引擎 (7)3.3.1检索式 (7)3.3.2检索步骤与结果 (7)4.检索效果评价 (10)4.1 检索词的选择 (10)4.1.1 从课题字面选择 (10)4.1.2 从课题内涵选择 (10)4.2 检索技术 (10)4.2.1 布尔检索 (10)4.2.2 限制检索 (10)4.3 数据库的选择 (11)5.文献综述 (11)5.1 绪论 (12)5.1.1研究背景 (12)5.1.2研究现状 (12)5.1.3研究目的及意义 (10)5.2 石油化工企业储罐火灾爆炸分析 (13)5.2.1储罐区发生火灾原因....................................................... 错误！未定义书签。
5.3 危险有害因素辨识与分析 (14)5.3.1 危险、有害因素的辨识和分析 (14)5.3.2研究甲醛储罐区火灾爆炸的危险评价 (15)5.4罐区火灾爆炸事故定量分析 (15)5.4.1影响火灾爆炸的主要参数 (15)5.4.2 DOW火灾爆炸指数 (17)5.4.3 ICI蒙德评价法 (16)5.4.4 两种指数评价方法的比较 (17)5.4.5 火灾爆炸事故树分析 (17)6.结论与展望 (17)6.1结论 (18)6.2展望 (19)1.课题分析安全文化的最先提出就是在前苏联的切尔诺贝利的核电站事故之后，1991年出版的(INSAG-4)报告即给出了安全文化的定义：安全文化是存在于单位和个人中的种种素质和态度的总和。
![苯并呋喃酮衍生物用于治疗和预防糖尿病的用途[发明专利]](https://img.taocdn.com/s1/m/598e57c47375a417876f8fa7.png)
专利名称：苯并呋喃酮衍生物用于治疗和预防糖尿病的用途专利类型：发明专利
发明人：王英,安托恩·德·赛茨厄,高德·斯查勒,丹尼尔·德欧拉兹,丹尼尔·若德斯托弗,斯文·沃尔夫拉姆,彼得·韦伯,
桑德拉·泰克赛拉
申请号：CN200480013108.9
申请日：20040505
公开号：CN1787815A
公开日：
20060614
专利内容由知识产权出版社提供
摘要：本发明涉及一种化合物用作在哺乳动物中预防或治疗糖尿病的有效试剂的用途。
所述化合物选自苯并呋喃衍生物的组，其显示出很好的降血糖效果，因此是在哺乳动物中预防或治疗糖尿病的有效试剂。
申请人：帝斯曼知识产权资产管理有限公司
地址：荷兰海尔伦
国籍：NL
代理机构：北京东方亿思知识产权代理有限责任公司
代理人：肖善强
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最新西湖旅游的英语作文精选3篇最新西湖旅游的英语作文精选3篇在平平淡淡的学习、工作、生活中，大家或多或少都会接触过作文吧，通过作文可以把我们那些零零散散的思想，聚集在一块。
那么一般作文是怎么写的呢？以下是小编为大家整理的关于西湖旅游的英语作文，欢迎大家借鉴与参考，希望对大家有所帮助。
最新西湖旅游的英语作文精选1Today, my brother took me to Hangzhou West Lake. The water of the lake is green, and the golden light on the water is very moving. As soon as the wind blows, there are layers of ripples on the water.There are also small carp in the lake. Some children are feeding them with bread crumbs. Two mandarin ducks are swaying towards us. The willows on both sides are green. Willow twists and turns, a breeze blows, willow branches dance with the wind, as if many little girls are dancing. Not far away, round dragonflies rest on the water lotus, just like their airport.I saw ships, big and small, sailing in the lake. I excitedly said to my brother, "I also want to take a boat.". Brother nodded and agreed. First we went to the wharf to buy tickets, and then we went on board again and again.When they were full, the captain sailed in the lake. I carefully looked at the scenery in the distance and suddenly found a bridge in the distance. I think it must be a broken bridge. I asked my brother, "is that a broken bridge?" he said, "yes, the legendary white lady and Xu Xian met on the broken bridge." When I looked towards the broken bridge, I found a very high tower, that is Leifeng T ower.We got under the boat quickly. I can't wait to run to SantanYinyue. I heard that there are 33 moons in Santan Yinyue. The blink of an eye time, we reluctantly left.今天，哥哥带我到杭州西湖游玩。
美国研制出“超视力保健饮料”
无
【期刊名称】《食品信息与技术》
【年(卷),期】2004(000)008
【总页数】1页(P15)
【作者】无
【作者单位】无
【正文语种】中文
【中图分类】TS275.4
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5.美国研制出基于Ⅱ型超晶格的1k×1k高性能长波红外焦平面阵列 [J], 高国龙因版权原因，仅展示原文概要，查看原文内容请购买。
高桩码头水下泥沙淤积和疏浚对桩的影响研究作者：蒋建平来源：《科技创新导报》2011年第08期摘要:本文分析了高桩码头水下泥沙淤积和疏浚,发现水下泥沙的淤积和疏浚对桩和岸坡的受力和变形都要明显的影响。
关键词:淤积疏浚泥沙桩高桩码头中图分类号:TU47 文献标识码:A 文章编号:1674-098X(2011)03(b)-0076-011 高桩码头水下泥沙的淤积和疏浚作为一种常用的深基础型式的桩基础,因其承载力高,能同时承受轴向和侧向荷载的作用,且适用于多种工程地质条件,已被广泛作为低承载力及中、高压缩性土层地区的重型建筑物,以及承受水平荷载为主的水工、港工、海工建筑物的基础中。
高桩码头就是桩基础在港口工程中的具体应用,它主要由作为上部结构的面板和面板下的桩基础两部分组成。
面板构成码头的地面,并把桩基础连成整体,直接承受作用在码头上的水平力和垂直力,并把他们传给桩基础,桩基础再将这些力传给地基。
高桩码头适用于软土地基,其应用很广。
高桩码头在使用过程中水下泥沙会发生淤积[1～3],特别是对河港和存在沿岸流的海港。
泥沙的淤积会使码头前沿水深变浅,影响船舶的进出港,因而必须进行疏浚。
高桩码头中岸坡-桩基础体系中桩基础与岸坡土体的相互作用非常复杂,而码头水下泥沙的淤积和疏浚更增加了这种复杂性。
根据高桩码头的实际调查,一般情况下高桩码头的使用寿命为20年左右[4]。
但很多高桩码头往往建成后10年之内即会出现破损现象,甚至无法正常使用;据我国对使用7～25年的高桩码头进行的抽查结果发现,有损坏或严重损坏的比例高达89%[5]。
码头破损后的修复往往是操作困难且代价高昂[6～8],有时修复的花费接近重新建造的花费,且修复后并不一定能达到理想的效果。
高桩码头破坏的原因是多方面的,是各种因素综合作用的结果。
各因素中的主导因素主要有岸坡-桩基础体系失调、地震、钢筋的锈蚀等。
导致岸坡-桩基础体系失调的因素主要有堆场土体向海侧的推挤作用、岸坡土体的自重作用、岸坡土体的固结或沉降对桩产生的负摩阻力(即下拉力)作用、码头水下泥沙淤积与疏浚的影响等。
Wharf embankment and strengthening program at the Port of OaklandFrank R.Lobedan *,Thomas LaBasco 1,Kenny Ogunfunmi 2ASCE,Port of Oakland,530Water Street,Oakland,CA 94607,USAAbstractThe wharf and embankment strengthening program (WESP)is a structural modification project involving approximately 12,000linear feet of pile-supported,marginal wharf structures.WESP is necessary because the Port of Oakland plans to deepen its berths from 2420mean lower low water (MLLW)to 2520MLLW,in conjunction with a Federal Government-sponsored channel dredging project.Unless they are structurally reinforced prior to the dredging,the waterfront components (i.e.wharves and embankments)will be weakened by the berth deepening project.WESP is a three-phase program that establishes the existing structural and seismic capacities of waterfront components,develops designs for improvements necessary to maintain these capacities after the berth deepening,and constructs the improvements.WESP also includes consideration of seismic upgrade improvements.The Port is currently completing the first phase of the WESP program.This paper will describe the design criteria,project phasing,construction type of waterfront components,project organization,and results to date for WESP.q 2002Published by Elsevier Science Ltd.Keywords:Wharf and embankment strengthening program;Mean lower low water;Waterfront components1.IntroductionThe Port of Oakland occupies 19miles (30.6km)on the eastern shore of San Francisco Bay reaching from the Oakland–San Francisco bay bridge to the Metropolitan Oakland International airport (see Fig.1).The maritime area of the Port consists of 1110acres (449ha)of terminal and support areas,including 27deepwater berths and 30gantry container cranes.The Port handles 98%of all containerized cargo that passes through northern California ports and is the fourth largest port in the United States.The Port is in the process of deepening selected berths in conjunction with a Federal Government-sponsored channel dredging project covering both the Inner and Outer Harbors (see Fig.2).The dredging project will deepen the Port’s channels and berths from 2420mean lower low water (MLLW)to 2520MLLW.The Port has carried out preliminary investigations to determine the structural capacities of the waterside crane rail girders and check the static slope stability of the embankments beneath the wharves for the proposed 2520dredge depth.The investigations found that modifications to the waterfrontcomponents (i.e.wharf structures and embankments)are required prior to the berth deepening.These modifications fall into two categories:1.Embankment stabilization .Installation of sheet pile walls at the toe of the embankments or some other form of ground stabilization improvement.2.Structural modifications to the wharves .The pile supported crane girders will require strengthening.Also,many existing batter piles will intrude into the berth area and will have to be replaced.Fig.3shows a transverse cross-section of a wharf and embankment together with the proposed modifications.The design of the modifications is required,at a minimum,to maintain similar structural capacity as currently exists prior to berth deepening.The objective of the Port’s wharf and embankment strengthening program (WESP)is to design and construct the structural modifi-cations necessary to mitigate the effects of the proposed 2520MLLW deepening project.In addition,WESP includes a seismic risk evaluation of its waterfront components in order to consider potential seismic upgrade improvements in conjunction with the design of embankment stabilization and structural modifi-cations.Conceptual seismic upgrade designs will be developed for increasing levels of seismically induced forces.Economic and risk analyses will then be utilized to0267-7261/02/$-see front matter q 2002Published by Elsevier Science Ltd.PII:S 0267-7261(02)00138-Soil Dynamics and Earthquake Engineering 22(2002)1125–1130/locate/soildyn1Tel.:þ1-510-627-1498;fax:þ1-510-627-9329.2Tel.:þ1-510-627-1481;fax:þ1-510-627-9329.*Corresponding author.Tel.:þ1-510-627-1265;fax:þ1-510-627-1877.E-mail addresses:flobedan@ (F.R.Lobedan),tlabasco@ (Basco),kogunfu@ (K.Ogunfunmi).determine the most cost-effective seismic upgrade alterna-tive for the specific waterfront components.2.Design criteriaThe analysis and design of WESP will be based on a revised Port of Oakland wharf design code.The Port is in the process of revising its wharf design code,which was originally adopted on May 1,1990.The revised code will be based on a multi-level,performance based design approach.The performance levels being proposed are as follows:†Level I:Establish ground motions having a 50%probability of exceedance in 50years.The wharf and embankment system shall be designed so that under this level of shaking,only minor,repairable damage is anticipated and that operations will not be interrupted.†Level 2:Establish ground motions having a 10%probability of exceedance in 50years.The wharf and embankment system shall be designed so that under this level of shaking,controlled,economically repairable damage is anticipated and that operations may be limitedand/or interrupted.In addition,collapse shall be prevented and damage shall be observable and accessible for repair.†Post-level 2:The wharf and embankment system shall be designed so that under this level of shaking,significant uneconomically repairable damage may occur,but will not be sufficient.†To endanger the life-safety of the users of the structure.Collapse shall be prevented.3.Project phasingWESP is comprised of three phases;a seismic analysis phase,a seismic upgrade planning phase,and a design/-bid/construction phase.These phases are further described below.Phase I:Seismic analysis to determine the current seismic capacities of waterfront components.AConduct analysis to determine the peak horizontal ground accelerations associated with the levels 1and 2performance criteria.Determine the associated prob-abilities of exceedance in 50years.BConduct analysis to determine the peak horizontal ground accelerations associated with the Post-level 2performance criteria.Determine the associated prob-ability of exceedance in 50years.CPrepare a wharf and embankment seismic risk evaluation report summarizing the results of the above analysis and describing the vulnerability and specific failure mechanisms of waterfront component.Phase II:Preliminary design of seismic upgrade improvements together with economic and risk analyses for consideration of seismic upgrade improvements.1.Develop preliminary design and associated cost esti-mates for improvements to waterfront components necessary to maintain an equivalent seismic risk for the future deepened berths (i.e.structural modifications necessary to mitigate the effects of the proposed 2520MLLW deepening project).2.Conduct seismic risk reduction planning at selected facilities.Develop conceptual strengthening concepts and associated construction cost estimates for up to four increasing levels of design associated with increasing levels of seismically induced forces.Evaluate seismic performance and expected damage that would result from a range of plausible earth-quake events for the region.Prepare corresponding repair costs and business interruption costs (i.e.operational costs)for the range of plausible earth-quake pute the mean value and standard deviation of total cost (strengthening costs,repairFig.1.Vicinitymap.Fig.2.Site plan.F.R.Lobedan et al./Soil Dynamics and Earthquake Engineering 22(2002)1125–11301126costs and operational costs)for the distribution of plausible earthquakes for each level of design.3.Develop port-wide strategy for implementation of WESPbased on business goals and the above analysis.Phase III:Implementation of WESP.Prepare plans and specifications to construct the structural modifications necessary to mitigate the effects of the proposed2520 MLLW deepening project together with the selected seismic upgrade improvements.Phase I was being concluded at the time of the preparation of this paper.4.General description of WESP berthsAs stated previously,only selected berths are being considered for deepening in conjunction with the Federal Government-sponsored channel dredging project.The berths selected are described in Table1and Fig.3.Berths23,24and25were constructed between1975and 1978and were previously designated as Berths2,3,4and5. These berths consist of three separate structures built at separate times.Berths4and5were constructed on eachside Fig.3.Transverse wharf section.Table1Berth descriptionsBerth identification#Year NotesBerth23a1978Original constructionBerth24,25b1975Original construction1500ext.at Berth241971Original constructionBerth26/301986Original constructionBerth35,371967–71Original constructionBerth35,371990Earthquake damage repairBerth60–631971Original constructionBerth67,681980Original constructionBerth691995Wharf extension at Berth68a Berths23was formerly designated as Berth5.b Berths24,25were formerly designated as Berths2,3and4.F.R.Lobedan et al./Soil Dynamics and Earthquake Engineering22(2002)1125–11301127of a150-ft wharf structure of yet another structural design. Each structure is separated from the others with a transverse, unkeyed expansion joint.With the exception of the150-ft extension,these wharf structures are quite similar consisting of an approximate2-ft thick reinforced concrete deck and an asphalt concrete pavement supported on18in.square,pre-cast,pre-stressed concrete piles.The lateral force resisting system consists of two sets of battered(4H:12V)piles.The 150-ft wharf section consists of a1–1/2-ft thick reinforced concrete deck ballasted with a3-ft layer offill and an asphalt concrete pavement supported on16in.square,pre-cast,pre-stressed concrete piles.The lateral force resisting system for the150-ft extension consists of a set of battered(4H:12V) piles.The land-side crane rail is not structurally connected to the deck and is supported on a grade beam.The structures are located on land reclaimed from the bay and are underlain byfill materials.The embankment beneath the wharf consists of sandfill,and young bay muds which slopes at a1–1/2H:1V and is armored by rubble.Although berths26and30were constructed at different times,they are all of similar design.The1090wide, reinforced concrete deck is supported by seven rows of vertical,24in.octagonal pre-cast,pre-stressed concrete piles.The concrete deck includes both crane rails.The embankment beneath the wharves consists of a rock dike, which slopes at a1–1/2H:1V.The lateral force resistance is provided by the back rows of vertical piles,which embed into the rock dike.Berths35–37were originally constructed between1967 and1971.The wharves as originally built are1–1/2-ft thick reinforced concrete deck ballasted with2–1/2-ft offill and an asphalt concrete pavement.The deck was supported on 16in.square,pre-cast,pre-stressed concrete piles with lateral force resistance provided by a row of alternating battered piles at the landward edge of the wharf.The land-side crane rail is not structurally connected to the deck and is supported on a grade beam.The structures are located on land reclaimed from the bay and are underlain byfill materials.The embankment beneath the wharves consists of sandfill,and young bay muds which slopes at a1–1/2H:1V and is armored by rubble.The Loma Prieta earthquake of1989caused extensive damage to the battered piles at berths35–37.The port constructed repairs consisting of two rows of vertical,24in. octagonal pre-cast,pre-stressed concrete piles,one at the landward row of original battered piles,and the other beneath the new land-side crane rail.An extension the concrete deck was constructed to connect the two rows of new piles,and the battered piles were cut off so that the new vertical piles provide the lateral force resistance.In addition,portions of the sandfill embankment were densified by installation of stone columns.Berths60–63were originally built in1971.The wharves are approximately1–1/2-ft thick reinforced concrete deck ballasted with2–1/2-ft offill and an asphalt concrete pavement.The deck is supported on16and18in.square,pre-cast,pre-stressed concrete piles with lateral force resistance provided by a row of alternating battered piles at the waterside edge of the wharf.The land-side crane rail is not structurally connected to the deck and is supported by battered piles.The embankment beneath the wharves consists of sandfill,and young bay muds which slopes at a1–1/2H:1V and is armored by rubble.Berths67–68were constructed in1980.The800wide reinforced concrete deck is supported byfive rows of vertical,24in.octagonal pre-cast,pre-stressed concrete piles.The landside crane rail is separated from the wharf structure and supported by a grade beam on battered piles. Berth69is actually a3000extension to berth68constructed in1995.It consists of a1090wide reinforced concrete deck supported by seven rows of vertical,24in.octagonal pre-cast,pre-stressed concrete piles.The concrete deck includes both crane rails.The embankment beneath the wharves consists of a rock dike,which slopes at a1–1/2H:1V.The lateral force resistance is supplied by the back rows of vertical piles,which embed into the rock dike.5.Project organizationThe port issued a request for proposals(RFP)for consultant services for the WESP.The RFP organized the work of WESP into seven contracts;two geotechnical contracts,four structural contracts and a seismic risk reduction-planning contract.Each contract reports directly to the port.The delegation of work is shown in Table2.The facilities were grouped in accordance with their structural similarities.6.Results to dateAs stated previously,at the time of the preparation of this paper,Phase I,determination of current seismic risk for existing conditions of waterfront components,was concluding.The geotechnical analysis methodologies used by the two geotechnical consultant teams were consistent[1,2].Static slope stability was analyzed using the limit-equilibrium method.Seismic slope stability analysis was performed Table2Delegation of workConsultant contract Berth identification#s Structural#123–25Structural#260–63Structural#330,67–69 Structural#435and37 Geotechnical#123–25and60–63 Geotechnical#230,67–69,35and37 Seismic risk reduction planning All berthsF.R.Lobedan et al./Soil Dynamics and Earthquake Engineering22(2002)1125–1130 1128using a pseudostatic approach.Slope deformations were estimated using the Newmark approach.In addition, computer code FLAC version3.4(two-dimensional,finite difference)was also used to evaluate seismic deformations of the embankment.The FLAC analysis was performed with and without the inclusion of piles in the embankment. Liquefaction susceptibility evaluations were also performed.The structural analysis methodologies used to determine the seismic capacity of the wharf structures varied.Three of the structural consultant teams utilized a simplified,two-dimensional pushover/response spectrum analysis[3–5].In all three cases,the computer program SAP2000was used for the analysis.The fourth structural team was assigned berths 60–63and utilized a three-dimensional time history analysis[6].The computer program ADINA was used for the3D analysis.Soil-structure interaction effects were incorporated in both the2D and3D models by providing ‘soil-spring’supports along the pile.Both the2D and3D modeling procedures decoupled the inertial seismic response from the embankment response.However,in one case,the two load cases(i.e.forces due to the structure’s inertial seismic response and those due to the embankment response)were combined to a certain extent(CH2MHill and B.C.Gerwick,Inc.May2000).A California Department of Transportation(CALTRANS)approach was adopted entitled‘CALTRANS Interim Seismic Design Criteria for Pile Survivability’.Phase I was intended to culminate in a relative ranking of seismic vulnerability of the selected WESP berths.Table3 shows a preliminary version of this relative ranking.7.ConclusionsThe engineering analysis performed on WESP to date has identified,in general,three failure mechanisms for the wharf structure/embankment systems when they are sub-jected to seismically induced forces.These behavioral effects are summarized as follows:1.Wharf structure’s inertial response.Response of thestructure under inertial seismic forces.2.Below-grade grade pile response.Response of the buriedportions of the structure to relative ground movements at soil boundaries.3.Embankment response.Response of buried portions ofthe structure to embankment deformations.The3D ADINA structural modeling captures the beha-vioral effects1and2.Presently,additional analysis is being considered to further calibrate the model.By using ground motions from the1989Loma Prieta earthquake as input to the model,the wharf structure/embankment behavior can be compared against the observed/recorded damage from the earthquake.The model can then be calibrated as appropriate.The2D SAP2000structural modeling captures behavioral effect1and behavioral effect3was incorporated to a certain extent.The geotechnical consultants provided lateral soil pressures intended to represent the limiting upper bound of soil deformations around the existing piles.Efforts are currently underway to determine if the FLAC results can be utilized to estimate behavioral effect2so that it can be accounted for in the analysis.Additional analysis may also be required to better understand the performance of the berth35–37wharf and embankment under seismic loading conditions.As stated previously,the structure was upgraded following the1989 Loma Prieta earthquake.The Phase I geotechnical analysis predicts significant ground spreading motion of the non-densified sandfill embankment,up to several feet of soil mass slide,at earthquakes of the same magnitude that achieves the Level I limit state of the structure.In the event of such slides,the16in.square piles of the original construction can be expected to fail catastrophically due to the drag forces exerted on them.The failure of several piles in a bent can be expected to result in an actual collapse of the deck above.This conclusion is of the greatest concern to the Port and does not coincide with the intent of the1989 upgrade.Further verification and validation of this con-clusion is necessary before proceeding with Phase2of WESP at this facility.The approach being utilized to validate the Berth35–37 Phase I geotechnical conclusions is to calibrate the FLAC model using the Loam Prieta ground motions.Input parameters will be adjusted in order to have the FLAC model predict the observed damage(i.e.slope deformations and pile damage)resulting from Loma Prieta.The resulting input parameters will then be used to revise the Phase I geotecnical report as necessary.Depending on these results, the Berth35–37Phase I structural report will most likely require revisions as well.Another interesting issue that resulted from the Phase I efforts to date is that the WESP geotechnical/seismological consultants have reported ground motions(peak ground accelerations and peak damped spectral accelerations)thatTable3Relative ranking of seismic vulnerabilityBerths identification#Probability of exceedance in50years(%)Level I Level II Post level IIBerth23604030Berths24and256035251500ext.at Berth24959545–35Berth262055Berth30262613Berths35and37602010Berth62656262Berth63706767Berths67and68502015Berth69303015F.R.Lobedan et al./Soil Dynamics and Earthquake Engineering22(2002)1125–11301129differ from values developed for other recent Port projects. The possible sources of the inconsistencies include differences in characteristics of the selected time histories, dynamic soil properties,and the techniques utilized to develop the site response analysis.In order to better understand the sources and signifi-cance of these inconsistencies,the port is planning to develop a procedure to ensure consistency in seismic design criteria across the entire Port of Oakland bound-aries.The procedure willfirst select a subsurface elevation below which soil conditions are consistent through out the Port area.Previous probabilistic seismic hazard analyses have developed stiff clay outcrop ground motions and target design response spectra.Utilizing this data as a basis,three sets of recorded acceleration time histories consistent with the seismological and geological conditions of the port area(and surrounding East Bay Area)will be selected and spectrally matched to the target design response spectra.Next,dynamic soil properties for the soil layers above the subsurface elevation of the stiff clay will be selected.Site response analyses will then be performed to deconvolve the spectrally matched time histories down to the subsurface elevation of the stiff clay and then back up to the subsurface elevation below which soil conditions are consistent through out the port area.Once this data has been established,soil profiles and embankment type(i.e.improved versus unimproved)will be examined in order to develop a seismic micro-zonation map for the Port area.The objective of the seismic micro-zonation map is to provide consistent seismic design criteria for the entire port area in a single document. References[1]URS Greiner Woodward Clyde.Port of Oakland Wharf andEmbankment Strengthening Program Berths60–63Geotechnical Report of Ground Motions.Technical report;26June2000.[2]Harding Lawson Associates.Ground Motion Report,Berths26–30,35–37,67–68ext.,Wharf and Embankment Strengthening Program.Technical report;24April2000.[3]CH2MHill and B.C.Gerwick,Inc.Wharf and Embankment SeismicRisk Evaluation Report,Berths23,24and25.Technical report;May 2000.[4]TranSystems Corporation and Han-Padron Associates.Seismic RiskEvaluation Report,WESP Phase I(Berths35–37).Technical report;1 May2000.[5]F.E.Jordan Associates,B.C.Gerwick,Inc.Phase I Seismic EvaluationReport,Berths26,30,67–68ext.Technical report;1May2000. [6]Brinkerhoff P,et al.Seismic Risk Evaluation Report,Port of OaklandWharf and Embankment Strengthening Program,Berths60–63.Technical report;25May2000.F.R.Lobedan et al./Soil Dynamics and Earthquake Engineering22(2002)1125–1130 1130。
