Search Results (2)

To study the force and deformation characteristics of a full-section immersed tube with post-pouring belt under the action of hydration reaction, the numerical model of full-section immersed tube with post-pouring belt was established by using MIDAS FEA (V2013) finite element analysis software, and the stress, cracking and deformation of the segment of the post-pouring belt were analyzed. The results show that under the action of hydration reaction, the concrete reaches the highest temperature at about 36 h, which appears at the roof of the tube gallery in the immersed tube, and the bottom steel plate expands rapidly initially, and subsequently shrinks gradually. The outer surface of the post-pouring segment concrete is stretched, and the internal region is under pressure, and as the internal temperature of the concrete cools down, the bottom plate starts to contract. The steel bar connection between the post-pouring belt and the surrounding immersed tube segment will increase the risk of cracking in the bottom plate of the full-section immersed tube. When only the steel bars in the bottom plate are connected, the maximum tensile stress of the immersed tube bottom plate will increase by 16.0% compared to the no connection case. If the steel bars of the immersed tube’s web and roof are also connected, the maximum tensile stress will increase by over 20%. By connecting the steel bars, the peripheral tube section plays a certain role in limiting the transverse deformation of the post-pouring belt and constraining the reinforcement of the bottom plate and web (and roof) can reduce the transverse deformation of the immersed tube to a great extent, reducing the proportion by over 10%. Full article

Tower foundations are generally of a cast-in-place structure with the disadvantages of low industrialization level and long construction period. The development of prefabricated foundation for transmission line projects is efficient to improve the industrialization level of the construction of tower foundation. In this study, the schemes of post-pouring belt U-shaped steel connection, post-pouring belt lap connection, grouting sleeve connection, and post-tensioned bond prestressed reinforcement connection, which have been widely used on building structures, are newly proposed to apply on plate foundation. The schemes were compared on processing, transporting, on-site constructing and performance. The pseudo-static tests on cast-in-place plate strip, post-pouring belt U-shaped steel connection and post-pouring belt lap connection plate strip were carried out. The results revealed that all the test plate bands were damaged in the bending mode, same as that of ordinary concrete. When U-shaped steel is adopted, more than 90% of the cast-in-place bearing capacity can be reached. The initial stiffness of prefabricated plate strip and cast-in-place strip is basically the same. The load-bearing capacity of the component is relevant to the anchorage length of the U-shaped steel. Although increasing the concrete strength of post-cast belt can improve the ultimate bearing capacity and shorten the construction period, the deformation capacity is reduced. Compared to other connection methods, post-pouring belt U-shaped steel connections have the advantage of simple construction, higher bearing capacity and stability. In summary, the post-pouring belt U-shaped steel connection scheme is recommended. Full article