Design and construction of high and large span cast-in-place reinforced concrete cantilever flowering frame beam

The high and large span cast-in-place reinforced concrete cantilever structure of the office building of some court, which is located I-steel at the cantilever and used steel pipe scaffold as the support, has guaranteed the frame body and structure security by the frame body calculating, on-site test and reasonable construction order.

Durability related environmental zonation and design methodology for marine RC structures

A reliability-based quantitative durability design methodology is presented for reinforced concrete(RC)structures in the marine environment on the basis of natural exposure data derived from four berths(1.5,1.5,4 and 15 years)of a concrete port.More than 200 chloride profiles are obtained and analyzed.The relationship between nominal surface chloride ion concentration and altitude is discussed.Subsequently,the formula of the apparent chloride diffusion coefficient is proposed with consideration of the surrounding temperature,sodium chloride solution concentration,age factor and altitude.Then,the reliability-based method to predict the durability of RC structures is developed according to Fick s second law.Relationships between the predicted penetration depth of the chloride ion,the ratio of the wetting time per-period and the corresponding altitude are discussed.Subsequently,the environmental zonation methodology is established for concrete structures under a marine chloride environment by considering the ratio of the wetting time per-period of concrete as the zoning index.Finally,the corres-ponding durability design method for each zone level is established,which contains the durability design regulations of the specimen,and correction coefficients for different water/binder ratios,ages,temperatures and chloride ion concentrations.

Research on the direct damage-based seismic design method of RC frame structures

Based on the existing research, this paper presents an innovative methodology to realize direct damage-based seismic design for RC frame structures by mobilizing ESDOF theory and the damage-based strength reduction factor（RD factor）. A design example is then followed to verify this method.

Strength&Conduct of Reinforced Concrete Corner Joint under Negative Moment Effect

The aim of our study is to reveal the effect of steel reinforcement details,tensile steel reinforcement ratio,compressed reinforcing steel ratio,reinforcing steel size,corner joint shape on the strength of reinforced concrete Fc'and delve into it for the most accurate details and concrete connections about the behavior and resistance of the corner joint of reinforced concrete,Depending on the available studies and sources in addition to our study,we concluded that each of these effects had a clear role in the behavior and resistance of the corner joint of reinforced concrete under the influence of the negative moment and yield stress.A study of the types of faults that can be reinforced angle joints obtains details and conditions of crushing that are almost identical for all types of steel reinforcement details and the basic requirements for the acceptable behavior of reinforced concrete joints in the installations and the efficiency of the joint and this may help us to prepare for disasters,whether natural or other,as happens with tremors The floor and failure that may occur due to wrong designs or old buildings and the possibility of using those connections to treat those joints and sections in reinforced or unarmed concrete facilities to preserve the safety of humans and buildings from sudden disasters and reduce and reduce risks,as well as qualitative control over the production of concrete connections and sections free from defects to the extreme.

The Structural Behavior of Low/Medium/High Rise Concrete Office Buildings in Kuwait

The main concern of this paper is to provide an extensive study for the structural behavior of low/medium/high rise office buildings aiming to deepen structure and architect designers understanding for such type of buildings. The study is performed on reinforced concrete and emphasized only on Kuwait city conditions for wind. Regular layout plan building with different heights ranging from five to fifty typical office stories are investigated in this study. Three dimensional finite element techniques through ETABS software are used in conducting analysis for structures presented here-in. A serviceability study is performed to ensure that buildings have sufficient stability to limit lateral drift and peak acceleration within the acceptable range of occupancy comfort. In addition, an ultimate strength study is carried out to design and verify that all the structural elements are designed to withstand factored gravity and lateral loadings in a safe manner according to the international building codes. The building slenderness ratio and the building core size and location are the studied parameters since they are the key drivers for the efficient structural design. Analysis results are presented and discussed and finally conclusions are summarized as guidelines for designers of concrete office buildings in Kuwait.

纤维增强复合材料加固混凝土桥梁结构研究进展

为总结纤维增强复合材料(FRP)在混凝土桥梁加固中的研究成果,拓宽FRP加固桥梁的思路,推动其在桥梁加固领域的广泛应用,阐述了FRP加固方法的发展及其特点,系统梳理了FRP加固方法在混凝土桥梁的研究进展。根据加固机理的不同,从抗弯加固、抗剪加固、抗压加固三方面加以归纳总结,介绍了几种常见的FRP加固方式、影响因素、破坏模式及其设计理论;分析了当前研究的不足,由此提出了一些可以继续深入研究的问题。结果表明:目前研究较多的有外贴FRP法、预应力FRP技术、表层嵌入法、FRP网格加固技术,其在不同的设计参数和使用条件下呈现出不同的破坏模式;外贴FRP片材容易过早发生剥离破坏,可以通过一些锚固措施提升界面黏结性,其中HB-FRP加固技术的锚固效果最好;预应力FRP加固技术因具有较高的材料强度利用率而展现出良好的应用前景;后续应深入研究FRP加固设计理论,综合考虑各参数对加固结构性能的影响,建立统一可靠且实用的计算模型;应进一步研究既有混凝土加固结构在多因素耦合作用下的长期性能和耐久性能,完善FRP加固混凝土桥梁设计方法和规范体系。

A Comparative Analysis for Land Utilization: Steel and R/C Interlaced Structures

In architecture,interlace structural concept is considered as a new design approach for cosmopolitan cities with high density to minimize the land use and increase the interaction.With various architectural approach,land resources can be minimized by this interlace concept for residential complexes.Such buildings will eliminate the reduction of land resource problem and on the other side safety measures in structural design is incorporated by interlace concept of buildings.This new concept can be constructed steel or reinforced concrete.In this paper,an analytical approach has been presented for these buildings in architecture and structural design.In the research,design considerations were taken for interlaced structures with reinforced concrete and steel.Components of steel structure,isolated footing,and columns.This paper is presenting a step wise process for interlaced structures.They are identification of project area,layout and model preparation,analysis and design of concrete interlaced structure,analysis and design of steel interlaced structure,drafting of the plans and costing and estimation of the structures.Comparison of both reinforced concrete and steel structures were carried out.The main aim of the paper is to provide a comparison between steel and concrete interlaced structure.A cost estimation was carried out to determine optimum design and construction for interlaced structures.

问题导向与成果导向相融合的钢筋混凝土结构设计原理课程教案设计

综合考虑钢筋混凝土结构设计原理课程章节内容较多的问题,进行合理的课程教案设计是目前较好地教授这门课的方法之一。首先,基于问题导向,总结各章节教学内容需要解决的关键问题;然后,基于成果导向,以问题导向中的各个关键问题为教学成果,开展各个章节的教案设计;最后,将钢筋混凝土结构设计原理课程中的主要章节内容整理成易于教学的教案,从而提升教师的教学能力和提高学生接受知识的能力。问题导向与成果导向相融合的教案设计方法可为土木工程专业其他相关课程的教案设计提供参考。

面向中外学生的混凝土结构教学实践与思考

该文分析“一带一路”倡议背景下留学生混凝土结构教学面临的国际化教学挑战,传统的混凝土教学模式在国外留学生加入教育背景下亟需改进。该文首先分析天津大学土木工程系留学生构成比例及混凝土教学所面临的不同国家混凝土设计规范差异,分析作者所教授的混凝土结构设计和全英文高等混凝土结构等课程特点,并提出加强课程思政、丰富教学方法、重视实习基地、因材施教调整教学内容和多重考核方式的课程教学措施。以期达到提升混凝土教学质量,提升中外学生培养质量,增强中外学生人才培养素质,助力我国“一带一路”发展建设。

考虑尺寸效应影响的钢筋混凝土构件纯扭承载力计算方法

近年来,钢筋混凝土构件的抗扭设计问题受到了广泛关注,现行的设计规范是基于小尺寸试件的试验数据外推而来,并未考虑尺寸效应的影响,对大尺寸试件承载力预测值的安全度有待商榷。对比分析国内外规范中RC构件纯扭承载力计算方法公式,基于钢筋混凝土柱纯扭加载三维细观数值模拟结果,总结钢筋混凝土柱名义抗扭强度尺寸效应规律,建立可定量反映配箍率影响的名义抗扭强度尺寸效应律公式;通过引入尺寸效应系数αh建立考虑结构尺寸效应影响的钢筋混凝土构件纯扭承载力建议预测公式,并将αh分为3个区域,综合考虑结构设计的安全性和经济性,从而保证大尺寸试件承载力预测值的安全度;通过与90个试验数据的对比,证明修正公式能有效提高大尺寸试件承载力预测值的安全储备。

河口船闸钢筋混凝土受盐水入侵影响的结构耐久性设计参数研究

河口船闸在服役过程中会受其下游海水入侵的影响,加之船闸运行时由于频繁灌泄水作用,使得船闸结构受盐水干湿交替的频次较海洋潮汐环境更高,混掺盐水高频率干湿交替的复杂环境下船闸钢筋混凝土(RC)易受腐蚀,结构耐久性问题突出。然而,针对河口船闸RC结构的耐久性设计参数目前未见明确的规范条文规定。为此,通过现场实测数据,推求得到了船闸工程建成后环境水中腐蚀因子对结构物的腐蚀程度,结合我国现行与混凝土耐久性相关的设计规范,经对比分析初定了河口船闸RC结构的耐久性设计参数(强度等级、水胶比、保护层厚度等)。在此基础上,综合考虑大体积混凝土在施工过程中的水化放热所引起的工程质量问题,依托既有工程的相关设计资料,提出了针对河口船闸RC受盐水入侵影响的结构耐久性设计参数建议值,以期为实际工程设计提供数据参考和技术支撑。

多塔大底盘RC框架隔震建筑抗震韧性设计研究

以位于Ⅷ度区(0.3 g)的某多塔钢筋混凝土(Reinforced Concrete,RC)框架建筑为研究对象,对其进行了大底盘隔震设计,研究了在设防、罕遇地震作用下3个塔楼的动力响应,并基于韧性评价标准对该隔震方案展开了2个地震水准下的抗震韧性评价。结果表明:隔震后结构基本周期延长至原来的3倍,降低了地震作用,有效控制了上部结构的地震响应。楼面绝对加速度的显著控制基本消除了加速度敏感型非结构构件的损伤。结构构件以及位移敏感型非结构构件的修复费用主导了建筑的修复费用。建筑的修复时间由阶段Ⅰ中结构构件的修复时间控制,此隔震方案下建筑的抗震韧性等级达到了三星。

矿渣基地聚物混凝土柱抗震性能研究

为了研究不同强度等级的矿渣基地聚物混凝土柱的抗震性能,设计了3个普通混凝土悬臂柱试件和3个矿渣基地聚物混凝土悬臂柱试件,通过低周反复荷载试验,对地聚物混凝土柱的破坏模式、裂缝发展、滞回性能、位移延性、耗能性能、刚度与强度退化和承载力等进行了评估,分析了混凝土种类、混凝土强度对试件抗震性能的影响。结果表明,在低周反复荷载作用下,与普通混凝土试件相比,矿渣基地聚物混凝土柱的抗震性能并未明显改善;提高地聚物混凝土强度会改变地聚物混凝土柱的破坏模式,从而对部分抗震性能(延性、耗能能力)产生不利的影响;验证表明《混凝土结构设计规范》(GB 50010—2010)中受弯承载力计算公式对于地聚物混凝土构件的计算结果偏小,拓展到工程应用中偏安全。

膨胀加强带替代伸缩后浇带的技术应用

膨胀加强带替代伸缩后浇带在实际应用中,能够有效地简化工序,减免裂缝产生,减少漏水隐患,实现大体量混凝土结构的持续浇筑,为缩短工期和保证质量带来显著效果。为此,结合工程实例的施工难点,分析膨胀加强带和伸缩后浇带的特点及区别,通过探究膨胀加强带替代伸缩后浇带技术的原理及在工程实例的实施情况,并对应用效果进行了总结。

钢筋混凝土柱-钢梁混合结构体系研究进展

钢筋混凝土柱-钢梁(RCS)混合结构体系由钢和混凝土两种不同的材料组成,综合了钢结构和混凝土结构各自优势,充分发挥材料性能,结构形式高效经济且低碳,是国内外研究和应用较多的结构体系之一。对国内外有关RCS节点基本受力性能、抗震性能、受剪承载力计算方法,整体结构抗震性能和抗连续倒塌性能,以及功能可恢复结构的研究现状和最新进展进行了综述和分析。对今后研究重点和发展趋势做了展望,对提高我国RCS混合结构研究和设计水平,推广RCS混合结构的工程应用,具有重要参考意义。

济南华润万象城抗震性能分析与设计

济南华润万象城为一栋结构高度412m的超限高层商业建筑,采用框架-剪力墙结构。结构中同时存在扭转不规则、平面开洞、大跨度结构、大悬挑结构、斜柱、桁架悬挑等多项平面及竖向不规则情况。采用多种计算程序进行了抗震性能分析,其结果均满足既定的抗震性能目标。对复杂商业中的各关键部位设计进行了多方案比选,确定了合理的结构布置和适当的构造措施,取得了良好的效果。

基于BIM技术的钢筋混凝土结构课程教学改革

传统钢筋混凝土结构课程中,学生往往通过施工图纸来学习各类构件的截面尺寸和配筋,但是图纸上内容繁多的标注以及与实际三维建筑结构的差别,让学生掌握起来较为费力。为了回归建筑的三维属性,帮助学生直观地学习本课程的相关知识,文章将BIM技术引入到课程教学中,基于BIM正向设计,在建模过程中将课程内容进行串联,实现从二维结构施工图到三维建筑模型的跨越,在激发学生积极性的同时,提升教学效果。

智能建造背景下混凝土结构设计课程改革探索

智能建造是以传统土木工程专业为基础,面向国家建设需求的新工科发展方向。混凝土结构设计课程作为传统土木工程专业的核心课程之一,仍是智能建造专业的重要教学环节。为了满足人才培养的新要求,结合目前国内高校智能建造专业的核心课程分析,探讨了现有混凝土结构设计课程知识的改革措施,构建了适应智能建造背景下程混凝土结构设计课程的知识体系,明确了混凝土结构设计在智能建造专业中的作用,相关成果可为智能建造专业结构设计教学提供参考。

现有建筑结构抗震鉴定及混凝土结构加固设计研究

虽然现有建筑结构具有较好的抗震表现,但是结构抗震性能依然是建筑设计中的重要内容,只有对建筑结构抗震鉴定和加固设计进行深入研究,才能进一步提升建筑的安全性。下面论述了现有建筑结构抗震鉴定流程和方法,分析了现有建筑结构抗震鉴定内容,并讨论了混凝土结构加固设计内容和方法,最后分析了加固设计的注意事项,并进行了总结。

高耸钢混结构造粒塔的定向爆破拆除设计及分离式共节点模拟研究

为成功爆破拆除复杂环境下85.8 m高钢筋混凝土结构造粒塔,结合塔身结构特点及周围环境情况,选用梯形爆破切口,开设高度对称的定向窗、定位窗,结合数据分析,最终确定切口圆心角为216°、切口高度为4.0 m,采用定向倾倒方式进行爆破拆除。为验证爆破设计方案的可行性,采用LS-DYNA仿真软件建立造粒塔分离式共节点三维有限元模型进行仿真计算。结果表明:总体方案的爆破技术参数选取准确;造粒塔往右偏移约4.9°,基本沿原设计方向倒塌,筒体轻微下坐,未发生前冲现象,拆除爆破效果达到预期目标。数值模拟结果显示,塔身顶端节点位移、速度变化趋势与实际倒塌过程基本一致。可为类似工程提供参考。