骨架沥青混合料与架构混凝土的对比

在农村道路建设讲求经济性、实用性的形势下,经过对沥青路面与水泥路面的骨架结构特点、形成等进行比较分析,可得出架构混凝土更适合农村道路建设的结论,这对低等级路面类型的选择具有一定的借鉴意义。

混凝土架构梁与锚杆在高边坡治理工程中的应用

为解决高边坡存在的滑坡、崩塌等地质灾害,本文结合某地质灾害隐患点治理工程案例,首先对地质灾害的成因作出分析。在此基础上,重点研究混凝土架构梁以及锚杆施工技术在高边坡治理工程中的应用。

从木结构到混凝土的穿越——北京传统牌楼主体架构从木制到混凝土的转变

牌楼是北京城标志性的传统构筑物,承载着深厚的城市历史文化内涵。传统木结构牌楼常因风雨侵蚀至材料糟朽而出现安全隐患。上世纪至今,混凝土技术的应用使得牌楼主体架构更加坚固也更耐腐蚀,而混凝土技术在有效传承古建筑文化的同时,也以自身的材料优势帮助我们追求既具时代感又有多样性的城市艺术设计理念。

高压输变电钢筋混凝土架构加固补强试验研究

为了改善变电站混凝土架构破损情况,以河北南网6个供电公司老旧变电站混凝土架构为例,提出了一套系统的修复方案,通过抗压强度及抗折试验分析了修复后混凝土试件的破坏形态及典型荷载-位移曲线,并与其他材料修复的混凝土试件进行对比,同时探讨了不同因素对极限承载力等主要参数的影响。结果表明,修复后试件的抗压、抗折极限承载力受界面隔离剂、修补材料的影响,且破损程度越大修复效果越明显。

煤矸石粗集料粒径对混凝土性能的影响

从混凝土架构结构模型出发,采用对比实验,研究了煤矸石粗集料粒径对混凝土坍落度、抗压强度、抗折强度、弹性模量和抗冻性的影响.研究结果表明,煤矸石粗集料对混凝土的坍落度、抗压强度、抗折强度和弹性模量影响十分显著.煤矸石粗集料的掺入降低了混凝土的坍落度和抗折强度,提高了混凝土的抗压强度和弹性模量,改善了混凝土的抗冻性.随着煤矸石粗集料粒径的增大,煤矸石混凝土的坍落度逐渐增大,抗折强度和抗冻性逐渐降低,而抗压强度和弹性模量变化并不显著.

优化混凝土结构加固方法的研究与应用

在我国经济迅速发展的今天,人们不仅仅对生活方式提出了较高的要求,更是在目前的住房建筑中有着更强的安全意识,在混凝土结构的建筑中,对于混凝土结构的坚固性十分的重要,所以在混凝土加固的过程中,对加固的方案需要进行仔细的考虑,在这些问题中,首先需要保证施工的安全性,同时对经济等效益进行一定程度上的考虑工作,保证在最后设计出合理的加固方案,取得良好的社会效益和经济效益。对混凝土在加固过程中的问题进行分析,有效的保证在混凝土加固过程中能够有效的保证其效果,取得良好的效益,并对此方法进行推广,更加的适合未来的应用。

Application of laminated vierendeel truss in high-position transfer story structure

To meet the demands for large space and flexible compartmentation ofbuildings, laminated vierendeel trasses are adopted in high-position transfer story structures.First the bearing characteristics are analyzed, in which reasonable stiffness ratio of the upperchord, middle chord, and lower chord is derived. Then combined with an actual engineering model (1:8similar ratio), the static loading and pseudo-dynamic tests of two models for laminated vierendeeltrass used in transfer story structures are conducted, in which one model adopts reinforcedconcrete, and the other adopts prestressed concrete and shape steel concrete. Seismic behaviors areanalyzed, including inter-story displacement, base shear-displacement skeleton curves, andequivalent viscosity-damping curves. A program is programmed to carry out the elasto-plastic dynamicanalysis, and displacement time-history curves of the two models are derived. The test and analysisresults show that the laminated vierendeel trass with prestressed concrete and shape steel concretehas excellent seismic behaviors. It can solve the disadvantages of laminated vierendeel trussesused in transfer story structures. Finally, some design suggestions are put forward, which can bereferenced by similar engineering.

Performance-based seismic financial risk assessment of reinforced concrete frame structures

Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be expressed either as a likelihood of damage or potential financial loss.Engineers tend to make use of the former(i.e.damage).Nevertheless,other non-technical stakeholders cannot get useful information from damage.However,if financial risk is expressed on the basis of probable monetary loss,it will be easily understood by all.Therefore,it is necessary to develop methodologies which communicate the system capacity and demand to financial risk,Incremental dynamic analysis(IDA) was applied in a performance-based earthquake engineering context to do hazard analysis,structural analysis,damage analysis and loss analysis of a reinforced concrete(RC) frame structure.And the financial implications of risk were expressed by expected annual loss(EAL).The quantitative risk analysis proposed is applicable to any engineering facilities and any natural hazards.It is shown that the results from the IDA can be used to assess the overall financial risk exposure to earthquake hazard for a given constructed facility.The computational IDA-EAL method will enable engineers to take into account the long-term financial implications in addition to the construction cost.Consequently,it will help stakeholders make decisions.

Performance-based passive control analysis of adjacent structures:Optimization of Maxwell dampers

The performance-based passive control analysis of the Maxwell dampers between one 10-story and one 6-story adjacent RC frames is conducted in this work.Not only the optimal parameters but also the optimal arrangements of the Maxwell dampers are proposed based on the optimal target of making the total exceeding probability of the adjacent structures to be minimal.The applicability of the analytical expressions of the Maxwell damper damping parameters under different seismic performance targets are firstly examined and then the preferable damping parameters of the Maxwell dampers are proposed through the extensive parametric studies.Furthermore,the optimal arranging positions and optimal arranging numbers of the Maxwell dampers between the adjacent buildings are derived based on a large number of seismic fragility analyses,as well.The general arranging laws of the Maxwell dampers between the adjacent buildings are generated based on the discussion of the theoretical method through the simplified plane model.The optimal parameters and optimal arrangement of the Maxwell dampers presented make both the adjacent structures have preferable controlled effects under each seismic performance target which can satisfy the requirements of multi-performance seismic resistance of the modern seismic codes.

Model Experiment on Integral Seismic Behavior of Reinforced Concrete Frame with Split Columns

Based on a series of previous studies, an experiment on the integral seismic behavior of a 1/3 scaled model of two-bay and three-story reinforced concrete frame with split columns at lower two stories is performed under cyclic loading. The original columns at lower two stories of the model frame are short columns and they are replaced by the split columns. The hysteresis curves between the horizontal cyclic load and the lateral displacement at the top of the model frame, indicate that under the cyclic loading, the model frame undergoes the process of cracking, yielding, and maximum loading before being destroyed at the ultimate load. They also indicate that the model frame has better ductility, and the ratio of the ultimate displacement to the yielding displacement, reaches 6.0. The yielding process of the model frame shows that for the frame with split columns, plastic hinges are generated at the ends of beams and then the columns begin yielding while the frame still possesses the bearing and deformation capacity. The design idea of directly changing the short column to long one in the reinforced concrete frame may be realized by replacing the short column with the split one.

Shaking Table Test on Out-of-Plane Stability of Infill Masonry Wall

The behaviors of infill wall in earthquakes show that infill masonry walls,which are used as nonstructural elements of concrete frames,are vulnerable when they are subjected to earthquake.In order to achieve an optimal antiseismic behavior,or even stability,two methods of connection are investigated.The shaking table tests,with 1:3 scale walls of two-storey model subjected to horizontal earthquake loads,were carried out to investigate the out-of-plane behaviors with different connections between walls and beams.The test results show that the connection methods employed between walls and beams have a significant effect on the out-of-plane stability of infill walls.The walls bound by bars with the beams perform better than those with inclined bricks without gaps.

Experimental Research on Seismic Performance of Storey-Adding Frame Structures

The seismic behaviors of an integral concreting frame, a light steel storey-adding frame and a storeyadding frame strengthened with carbon fiber reinforced polymer(CFRP)were investigated under low-cycle and repeated load(scale 1∶3). The failure characteristics, hysteretic behavior, rigidity degeneracy, deflection ductility and energy-dissipation capacity of the three specimens were compared. The test results reveal that chemicallybonded rebar technique can meet the requirements of storey-adding engineering. The carrying capacity, the deflection ductility, the energy-dissipating capacity and seismic performance of the light steel storey-adding frame are higher than those of the integral concreting frame, and they are the highest in the storey-adding frame strengthened with CFRP.

Design of Dissipative Braces for an Existing Strategic Building with a Pushover Based Procedure

The research presented in this paper deals with the seismic protection of existing frame structures by means of passive energy dissipation. An iterative displacement-based procedure, based on capacity spectrum, to design dissipative bracings for seismic retrofitting of the frame structures is described, and some applications are discussed. The procedure can be used with any typology of dissipative device and for different performance targets. In this work, the procedure has been applied, with both traditional pushover （load profile proportional to first mode） and multimodal pushover, to an existing RC （reinforced concrete） frame building. In the application, the buckling restrained braces have been used in order to prevent damages to both the structure and non structural elements. The use of multimodal pushover proves to be more effective than pushover based on single mode in case of medium rise RC frame building （higher than 30 m） but, once this building is retrofitted, and therefore regularized, with a bracing system, the difference between using monomodal or multimodal pushover becomes insignificant.

Extension of Direct Displacement-Based Design to Plan-Asymmetric RC Frame Buildings

The object of this paper is the evaluation of the seismic response of reinforced concrete frames designed according to the DDBD （direct displacement-based design） approach. The great part of research works about DDBD has been dedicated to planar frames, but recently also some proposals for 3D structures have been presented, in particular for wall structures. This paper will give a further contribution to the extension of the procedure for the case of plan-asymmetric RC （reinforced concrete） frames. The extended methodology is aimed at accounting for the floor rotations on the basis of a given lateral strength distribution along the plan. The procedure was applied to two plan-asymmetric RC frames, characterized by the same geometry but different lateral strength distributions along the plan. The seismic behavior of the designed frames was studied by adopting a fiber model and by performing pushover and nonlinear dynamic analyses.

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.

Improved modal truncation error in the directly analytical method for damage identification of frame structures

The damage identification is made by the numerical simulation analysis of a five-storey-and-two-span RC frame structure, using improved and unimproved direct analytical method respectively; and the fundamental equations were solved by the minimal least square method （viz. general inverse method）. It demonstrates that the feasibility and the accuracy of the present approach were impoved significantly, compared with the result of unimproved damage identification.

Application Example of Reinforced Concrete Frame Structure Waste Dam in the Proiect of Valley Sanitary Landfill

waste dam is one of the most important infrastructures in the project of valley sanitary landfill. On one hand, it forms the landfill capacity required. On the other hand, it improves the slope stability of waste body. Consequently, I think it is very significant to maintain the stability of waste dana for the whole sanitary landfill. Combining with a project example, aiming at the special geological conditions, we have made three plans of waste dam structure, calculation and analysis comparison respectively. Reinforced concrete frame waste dam is highlighted in the project for its advantages, smoothly solving the three problems in the engineering.

Optimization of Reinforced Concrete Cum Masonry Construction

In design and construction of low/high rise buildings, different forms of construction can be applied such as concrete shear wall structural system and framed structural system without or with masonry infill walls. At present, most buildings in East Africa are constructed as reinforced concrete framed structures with strong masonry infill, but during design, engineers assume that the masonry infill panels have zero contribution in offering load resistance. Due to the problem above, a study with an objective of finding out the influence of masonry panels on the properties of reinforced concrete infilled frame under vertical load has been done. Three types of models： reinforced concrete frame model, masonry model and reinforced concrete frame with masonry infill, were investigated using finite element technique. In additional to the finite element analysis, laboratory models were prepared and tested so as to check the validity of the analytical results. The obtained results have led to an establishment of a mathematical model which may be useful to the design engineers since masonry wall panels can now be considered as load bearing elements. Such consideration of frame together with masonry leads to an accurate and optimal design of the frame, resulting into lesser amount of reinforcement and geometrical properties of the frame.

Earthquake Response Characteristics of Contained Masonry Infilled Frames

The strength and stiffness contribution of infill masonry is generally ignored in the design, due to the uncertainty in the strength properties of masonry, separation of infill from frame, low tensile strength, brittle characteristics of masonry walls, less out of plane strength and stiffness, etc.. They are considered as nonstructural elements which is reasonable for the frames under gravity loads but it is not true for the frames under seismic loads. Contained masonry as infill in RC （reinforced concrete） frames provides better contact at the interface and a higher out of plane strength and stiffness. Considering the seismic action on the frames which are likely to be subjected to in-plane as well as out of plane shaking, a research work has been carried out by the authors to investigate the seismic performance of RC frames with and without contained masonry infill panels using FE （finite element） computer program （ANSYS-Ver. l 1） and experimentally using the tri-axial shake table to evaluate the methods proposed in IS-1893-2002 to calculate the fundamental natural frequency. The RC frames were designed and detailed as per IS （Indian Standard） specifications such as IS 456-2000, IS 1893-2002 and IS 13920-1993. Based on the experimental and analytical investigations, the contained masonry infill panels significantly affect the seismic load resisting characteristics of the RC frames. The IS 1893-2002 formulation does not predict the values and hence the recommendation needs to be validated with experimental results.

Research on Seismic Reliability and Damage of Reinforced Concrete Frame

This paper first introduces the basic principle of seismic risk analysis, and then put forward the basic concept of structures global seismic fragility, aiming at the existing problems of traditional analysis method, combined the method of analytical approximation degree of structure reliability with Performance-Based Seismic Design （PBSD）, put forward the analysis method of structural reliability and the performance of the global seismic fragility, are calculated by using the finite element reliability method of structures global seismic fragility. Taking the maximum interlamination relative deformation as indicators of overall performance, we analyze seismic fragility of five storey RC frame structure, rendering the seismic fragility curves corresponding to different performance requirements and different earthquake action.