Applied Mechanics and Materials Vols. 578-579

Abstract: This study applies the nonlinear finite element analysis software LS-DYNA to conduct a numerical simulation of damage mode of reinforced concrete slab under complex boundary condition subjected to air blast load. The factors affecting damage model of reinforced concrete slab, standoff distance and explosives location, were analyzed. The results show that: With the increase of the standoff distance, the failure mode of RC slab gradually changes from localized punching failure to shear failure at the support. With the location for explosive changing from the center of RC slab to the beam plate combination, the failure mode of RC slabs gradually changes from localized punching failure to bending-shear failure under close-in blast loading.

Abstract: Canal bridge and aqueduct main foundation types include well column, pier, bored piles, bent pile etc. Most of these foundations are in low-lying conduit. The water content of foundation soil is very rich. Especially pile foundation in the drain, due to the high underground water level, pile foundation around soil is in a state full of water. So such type of foundation freeze injury phenomenons are very serious. In order to solve such freeze injury problems, some antifreezing measures are adopted.

Abstract: In this paper, a further research has been carried on mechanical properties of concrete filled steel tube reinforced concrete columns after exposure to fire. A finite element analysis (FEA) model for concrete filled steel tube reinforced concrete columns after exposure to fire under axial compression is developed by ABAQUS. The temperature of cross-section element after exposure to fire has been obtained. The FEA model of temperature field is then used to investigate the mechanism of such composite columns further. Influences of parameters on Load-bearing Capacity such as fire duration time and steel ratio were analyzed. The work in this paper provides a basis for further theoretical study on concrete filled steel tube reinforced concrete columns after exposure to fire.

Abstract: This paper focuses on research into prestressed I-beams made of ultra-high-performance concrete, which are designed to be structural elements in small and medium span railway bridges. Prestressed concrete I-beams are designed with ten prestressing cables in the bottom flange. The prestressed beams are laid close together in the actual structure with panels inserted between them. The entire structure will subsequently become monolithic. At the present time, I-beams made of rolled steel are commonly used as structural elements in this type of structure. The advantage of these types of structures lies in their having a low construction height. This paper presents a computer and experimental analysis of the loading of UHPC prestressed I-beams. For the purpose of the experiments, several specimens of 7 m span were made. The specimens were subsequently tested in the laboratory in four-point bending tests. The paper presents the process and results of the experiments. Simultaneously with the experiments, computer analyses were created in which optimization of the material and geometric parameters of the beams were carried out. The paper demonstrates the correspondence of the experimental and computer-simulated load test results.

Abstract: A finite element method was developed to investigate the semi-rigid connection mechanical behaviors in the process of CFST structures progressive collapse, and different semi-rigid connection joint stiffness were taken into consideration and compared to rigid connection. Nonlinear static and dynamic analysis were carried out with alternate path method. The numerical result shows that the increase of joint stiffness would evidently enhance the structural progressive collapse resistance performance, and CFST structures have excellent characteristic to prevent progressive collapse, the great deformation capacity and energy dissipation ability of semi-rigid connections are advantageous to progressive collapse resistance.

Abstract: This essay introduces a construction case of demolishing the scrapped concrete overpass over the existing railway using the mobile protective scaffolding during the construction of an overpass reform project. When the overpass demolishing project is staging into the phase of right over the railway, moving the mobile protective scaffolding to the appropriate position guarantees an easy way for the demolishing of the scrapped overpass above as well as a safe journey for the railway. After the demolishing project, the scaffolding can be removed and dismantled. The stability of the mobile protective scaffolding structure and the design of the member response is discussed in this essay, meanwhile the controlling key points of the scaffolding during the construction is also sketched.

Abstract: Glass curtain wall supported by plane cable net (PCNCW) is very popular in civil engineering for its advantages of beautiful appearance and good permeability etc. Because plane cable net (PCN) has the obvious geometrical nonlinear character and its dynamic response is affected by the main structure it attached to, it has to be considered particularly in wind-resistant and seismic design. In recent years, many research results have been achieved on wind-resistant and seismic performance of PCNCW, including the study on how to calculate the equivalent static wind and seismic load, how the factors influence the wind-resistant force behavior, discussion on seismic fortification criterion, and how it is influenced by the main structure under wind and seismic load. These results are overviewed and the problems needed to be further studied in the future is prospected.

Abstract: It adopts the finite element analysis method, researches the stress state of the composite wall interface of bar-type composite wall structure just under the certain bias loads. The Bar-type composite wall structure under bias load, then the stress distribution rule of the windward side and leeward surface is near with the thermal insulation layer. On the wall, the stress is larger of the upper and below part of wall, the middle part of the interface tangential stresses are zero; the upper end wall supports the maximum interfacial normal stress.

Abstract: GengYuHe bridge was a prestressed concrete continuous box girder bridge,based on the static load test of single beam bridges compared with theoretical calculation value,check whether the actual control section stress of the bridge are in conformity with the design requirements,and give advice.

Abstract: Based on the experiments of joint with exterior diaphragms between concrete-filled square steel tubular column and H-type steel beam under cyclic loading, with appropriate material stress-strain relations and failure criteria, the mechanical properties of this type of joint were researched by using ANSYS,finite element analyses were conducted under cyclic loading, the hysteretic and framework curves of this type joint between test and theoretical were researched. The study results showed that all specimens have good ductility and energy dissipation capacity. The story angle drift ductility ratios areμ=3.07~3.66,the elastic and elastic-plastic story angle drift are Φy=0.0041~0.0047 and Φu=0.0124~0.0172,and the equivalent viscous damping coefficients are he=0.26~0.35,which meet the needs of the current code for seismic design of building.