Advanced Materials Research Vols. 163-167

Abstract: Design theory of high or large-span form strut system cann’t meet the engineering requirement and deficiencies were pointed out. In this paper, variation rule of axial force of the strut with the whole course of concrete pouring had been studied by measuring on three sites. The result discovered that pouring method and floor modes have significant effect on axial force of high or large-span form strut system. Compared to manual pouring, pumping lead to not only horizontal impact force but also vertical impact force. Compared to flat roof, axial force of avertical strut in sloping roof form strut system were more uneven and the maximal difference reached to 2 times. Axial force between bottom part and top part at avertical strut are different due to the influence of horizontal strut and crossing strut. Due to analysis result, some corresponding advices were put out in the end.

Abstract: Large-Area Concrete beam-slab Structure mainly means the monolithically cast concrete structure whose length and width are more than the maximum of the structure in the code. The influence of temperature change, shrinkage and creep on structure is the key to solving the problem. Through a practical engineering, Shrinkage and creep formulas accord with test results are brought forward. The calculation results of shrinkage strain, temperature strain and prestressed strain coincide test results and can be directed to the projects.

Abstract: Reinforced concrete is the current main material to build liquid-storage structure. Because coarse aggregate and fine aggregate have different expansion coefficient under thermal environment, the expansion crack and leakage will happen. it will make liquid-storage structure failure. So thermal effect has become the most important factor that can not be ignored in the structure analysis and design. In this paper, adopting FEM software ANSYS, considering four-cell reinforced concrete rectangular liquid-storage structure at different temperature, heat-solid coupling numerical simulation analysis is proceeded, and the axial (shear) force and bending moment distribution are obtained.

Abstract: Based on the limited demand of transfer beam sectional dimension of tall building structure with transfer story in Technical Specification for Concrete Structures of Tall Building, a high-level transfer frame-shear structure with viscous dampers is presented for simulating the mechanical behavior of the key components effect with consideration the transfer beam depth with 1/6, 1/8 and 1/10 calculation span. The analysis results indicate that the internal force of the transfer beam, frame-support column of transfer story, shear wall above transfer level and base shear wall is obviously reduced, with the reduction of the transfer beam depth. Comparison with the high-level transfer frame-shear structure, the internal force of the key components of the high-level transfer frame-shear structure with viscous dampers also is reduced. Therefore, the limited demand of the transfer beam sectional dimension and the construction measure of the shear wall could be properly reduced in the high-level transfer frame-shear structure with viscous dampers.

Abstract: Owing to their importance to the assessment of reinforced concrete structures, it is of great practical significance to predict the elastic moduli of concrete with interfacial cracks. The intention of this paper is to present an analytical solution for the elastic moduli of cracked concrete. According to the theory of stereology, the 2D scalar crack density is expressed as an explicit function of the aggregate area fraction and the central angle of interfacial cracks. For uniformly oriented and mutually interacted interfacial cracks, the effective medium method is used to derive the relative elastic moduli of cracked concrete. Based on the numerical results, it is found that the relative elastic moduli decrease with the increase of the aggregate area fraction and/or the central angle of interfacial cracks. It is also found that the relative elastic moduli are independent of the minimum aggregate diameter, the maximum aggregate diameter, and the aggregate gradation.

Abstract: In order to study the bonding characteristic of the BFRP(Basalt Fiber Reinforced Plastics for short) bars and the basalt fiber reinforced concrete, the BFRP was embedded into the cubic concrete specimen which mixed the basalt fiber sized the edge length 150 mm. By changing the diameter of the BFRP, the bonding length of the BFRP and the basalt fiber volume content of the basalt fiber reinforced concrete, the experimental results indicate that the average bonding strength decreased while the bonding length increased and it become weaker while the diameter of the BFRP was bigger, and it shows the best effect of the bonding strength when its fiber content was 0.1% comparing with three kinds of fiber content. The bond-slip constitutive model of BFRP bar and the basalt fiber concrete corresponded to the continuous curve model.

Abstract: With the increasing volume demand of silos, silo diameters are bigger and bigger. However, present wall pressure computation methods are mostly based on small diameter silos. To solve this problem, systematical research on the wall pressure in large diameter silos is of great importance. For now, in the Chinese code the wall pressure computation methods are based on the limit equilibrium theory to be calculated, which define the orientation of the rupture plane in the bulk solid within the silo. The rupture angle is a key parameter to silos’ wall pressure. Therefore the value and direction of rupture angle are researched by theoretical method in this paper, which has heavy significance and provide an important basis for the large diameter silo design.

Abstract: This paper presents a numerical strategy to model nonlinear damage behavior of RC members based on level of material. The first part of the paper presents a numerical model of the RC member based on the Timoshenko multifiber beam elements and non-linear damage constitutive laws for concrete, and the effective three dimensional fiber beam-column element model is developed for the nonlinear damage analysis of RC members with VUEL subroutine based on ABAQUS/Explicit platform. In the second part, a nonlinear damage analysis for RC members is established by analyzing the sections of fiber beam column elements, and the member damage index through statistical analysis of concrete fibers damage is defined in the extreme section of beam elements, which can describe the nonlinear damage behavior of RC members under any loadings. Accuracy of the model is identified preliminarily by comparing with the analysis results of solid elements, the results shows that it seems now possible to use this approach to investigate numerically the nonlinear damage behavior of RC members based on level of material.

Abstract: Under the Large Tonnage Pre-Stress, the stress of concrete which is under the anchor plate is complicated. To ensure the safety of construction and structure, the condition of local stress of the bridge structure should be investigated. When the pre-stress steel of Segment 1# of Pier 1# of Hongwuwo Bridge is tensioned, the strain situation of concrete near the anchor plate of the box girder is measured. The measured value is compared with the analytical value which is obtained through space finite element method.

Abstract: Landslide, rock falling, river erosion are the serious geological disasters that make effect on Zhongxian-Wuhan gas pipeline safety, and the landslide is the most outstanding disasters among them, and anti-slide pile was often used to reinforce landslide mass. However, computation and design of anti-slide pile approximation in actual`dge issues that worth further studying. Irrational design of anti-slide pile can result in landslide risk still exist, landslide is still possible to failed, and conservative design although eliminate landslide risk, and at same time it causes waste of money. So it has important theoretical and engineering significance to verify the accuracy of the design and assess control effectiveness of landslide based on internal force monitoring of anti-slide pile. Based on axial force monitoring main reinforcement inner anti-slide pile, this paper gets the factual moment variation of anti-slide pile of Shunxi No.1 at different times, and compared factual moment with theory moment calculated by the commonest M method. The result showed that the theory measurement calculated by M method is much more then factual moment, so it is safe to compute internal force of piles by M method. Currently, it indicates that the landslide after treatment is under a stable state because of less stress acting on the pile, and the main threat to the gas pipeline will vanished, and the expected control aim is achieved. It has great reference for internal force design of anti-slide pile retaining structure and control effectiveness evaluation.