Papers by Author: Shun Bo Zhao

Abstract: Eleven pre-cracking reinforced concrete T-beams were strengthened with U-stirrups and longitudinal sheets of CFRP, the main parameters were the width, layer and space of U-stirrups of CFRP. The tests for shear resistance of the beams were carried out to measure the diagonal crack development and crack width, mid-span deflection, CFRP strain and ultimate resistance. Compared with the reference beam without strengthening, the diagonal cracks were effectively restrained and the shear resistances of the beams were also strengthened by the U-stirrups of CFRP. However, the shear resistance increment of the beams were not in direct proportion with the amount of CFRP sheet characterized by the width, layer and space of U-stirrups, as the strengthening effect is obviously influenced by the bond quality and the anchorage reliability of the U-stirrups. When strengthened with one layer, the shear resistance of the beam was enhanced largely by the wider sheet. When strengthened with two layers, the enhancement of shear resistance was weakened with the increasing width of sheets.

Abstract: This paper introduces the experimental results of long-term carbonization of concrete with machine-made sand (MSC), which is part of the studies on durability of this new concrete. Three strength grades of concrete C30, C40 and C50, and the contents of stone powder in machine-made sand of 5%, 9% and 13% in mass were considered in the mix proportion of concrete with machine-made sand. The ordinary concrete with natural river sand in the same strength grade was tested at the same time for comparison. The test was conducted for 360 days, and the results showed that the carbonization of MSC was similar with that of ordinary concrete, the carbonized depth increased with the increasing carbonization time. The carbonization was rapid at initial before 28 days, and became slowly with the time going by. The content of stone powder in machine-made sand affected the carbonization of MSC in some extent, which should be limited in a reasonable range. Based on the test data, the formulas for forecasting the carbonized depth of MSC are suggested.

Abstract: Under the background of engineering application, a 3-D FE analysis was carried out to evaluate the loading performance of a two-hole pair-arch tunnel under-across the main canal of South-to-North Water Transfer Project. In fact, the tunnel was constructed in integral longitudinally without obeying the design requirement of parting within certain length. The analysis showed that the vertical deformation and tensile stress along the longitudinal axis are obviously affected by the loads from main canal, moreover, the tensile stress exceeds the limit of tensile strength of concrete, which may lead thoroughly cracks on top plate of tunnel. This analysis determined the crack zone which should be dealt with.

Abstract: Nonlinear three-dimensional finite element method was used to analyze the crack pattern and stress distribution of reinforced concrete frame exterior joints with T-section columns. On the basis of the smear-crack approach, the cracking of reinforced concrete joint was predicted. And the capability of finite element model was demonstrated by comparing the predictions with test results. Further analysis was carried out to study the effect of axial load ratio and limb length on stresses of the joints. It is seen that the stresses of joint were influenced by these two factors, which should be considered in the design of reinforced concrete joint with T-section column.

Abstract: On basis of summarizing the traditional design methods on road passenger station, this paper discusses the influence of road passenger station layout on scale design. Combined with the analysis of layout design method for road passenger station, a bi-level programming model is proposed taking into account the overall optimization design problem of the scale and the location of the road passenger station. Through a numerical example analysis, an optimized station layout plan and an optimum volume allocation of the station are given out.

Abstract: The steel-polypropylene hybrid fiber reinforced concrete can take full advantages of macro-scale crack resistance and toughening effect on the concrete matrix of steel and polypropylene fibers. The shortcomings of concrete are improved and there is a wide prospect application in engineering. This paper summarizes the enhancement theories of hybrid fiber reinforced concrete to explain its strengthening mechanism. The research status is reviewed including mix proportion design, working performance of fresh concrete, mechanical behaviors, durability (impermeability, shrinkage and others), and engineering applications etc. Some further researches are forecasted. It would be very useful to apply and popularize steel-polypropylene hybrid fiber reinforced concrete.

Abstract: As the requirements of traffic functions and urban landscape, a reinforced concrete arch- deck bridge is designed with archaized connective corridors. The main dimensions and drawings are introduced and the static analytical results of the bridge are discussed in this paper. The numerical model was built by the integrated solution system for bridge and civil engineering- MIDAS/Civil. The results show that the temperature of bridge and the horizontal shift at arch toes due to sedimentation play important roles sensitively influencing the bending moments and displacements of control sections. Compared numerical results of the bridge only with dead loads, the maximum bending moments and displacements would reach 3.81 times and 6.52 times respectively. The axial force of arch is mainly resulted from dead loads, which gradually increases from arch crown to arch toes. The design and numerical results would give some references to similar bridges.

Abstract: Based on the experimental studies, finite element models were built using ANSYS software to simulate the bond properties of steel bars in machine-made-sand concrete (MSC), which considered the nonlinear bond behavior of interface between steel bar and MSC. The concrete strength and the bond length of steel bar are considered as the main parameters for calculation. The complete bond-slip curves of plain and deformed steel bars are well simulated comparing those obtained from the experimental studies. The study gives an theoretical method to analyze the bond properties of steel bar in MSC.

Abstract: To meet the requirement of machine-made sand application in concrete structures, experimental studies were carried out on the bond of plain steel bar with Machine-made Sand Concrete (MSC) by the central pull-out test method. Three specimens were cast as one group, 14 groups were tested considering the influence of concrete strength, bond length and stone powder content in machine-made sand. Based on the experimental research, the characteristic values of bond-slip curve such as the initial-slip and ultimate bond stresses with corresponding slips are statistically analyzed, the bond-slip constitutive relations between plain steel bar and MSC were obtained.

Abstract: Combined with the actual engineering, this paper presents the construction technology for the transverse bonded structural steel for PPC hollow slab bridge. The steel plate and channel steel were first respectively bonded on the top and bottom of the PPC hollow slab by structural adhesive, and then they were connected by bolt. The transverse connection is formed between hollow slabs to enhance the structural integrity of the bridge. The bolt connection may subject to the structural adhesive fatigue failure due to vehicle loads. Compared with other strengthening method, this method has the advantage of saving investment and construction time.