Applied Mechanics and Materials Vols. 94-96

Abstract: The combined connection with welds and bolds can be widely used in reinforcing the joint in steel structure. In this paper, proposed design method of combined connection with bolts and longitudinal welds was given based on the tests and finite element analysis (FEA). The method considers the effect of the strength ratio between bolts and welds. The safety and reliability of the method were verified by FEA and comparison with other design method. The design method can contribute to the promotion of the application of the combined connections.

Abstract: It is described in detail how to develop the intelligent instrument system through connecting bus-bridge of PROFIBUS with single-chip microcomputer system of users, changing the traditional PLC-control into the data-bus control in limekiln electrical control system. This paper focuses on the development of hardware of the accompanies-station of PROFIBUS-DP, the model for user, and software design. About 400,000 dollars per each were saved and the ease of operation and the robust of control have been also improved dramatically after novel development.

Abstract: During constructing of lifting-up engineering of Humanity Hall of Nanjing Museum, the sizes of steel lifting supports, loads distribution and lifting force changes were surveyed, which controls the safety of Lifting-up engineering. By establishing limit state function of H-shaped steel lifting support, based on those data, the reliability of lifting supports at three states of design, weighing after columns cut and lifting process was calculated respectively using checking point method. Results shows: the reliability in constructing process of building reconstruct engineering is lower than that of general engineering because more difficulty in construction, and in lifting process the time-dependent reliability of KZ1 is lower 63.1% than design reliability.

Abstract: Based on the theory of linear elastic fracture mechanics, formulae for the circumferential stress and the initial fracture point around flattening elliptical hole under compression were derived. When considering the expansion of closed crack under pressure, by introducing the effective friction coefficient f obtained the advantages derived crack angle and the friction coefficient of the crack surface had inversely proportional relationship. Use the software RFPA2D to simulate the rock samples with pre-fracture. The results show that the plane of weakness occurred fracture firstly that lead to the weakness plane through and then formed to be cracks. With the axial displacement exerting, the through crack occurred closure, the end of the rock fracture produced a curved path expansion at the same time. The final destruction face of the rock is approximately a 450 slip-line. It shows that the final failure mode of the rock is compression and shear failure. Different crack angles make the differences of initial cracking angle, but the crack propagation mode and its ultimate failure mode are similar, while have no affect on the carrying capacity.

Abstract: The paper focuses on the value of the foundation’s rotation of the light steel portal-rigid frames which is caused by the upper uneven loads .It analyzes the effect of the rotation of the foundation on the internal force of the upper structure. It calculates the values of the rotation and the influence to the internal force of the upper structure respectively under four different load conditions which are constant load, live load, wind load, and crane load. It draws a conclusion that the additional internal force which is caused by the rotation of the foundation is large. If not consider the effect in the design, the structure is unsafe.

Abstract: Structural health monitoring (SHM) has been applied to huge and important civil structures. Its role is for obtaining readings of sensors, analysis for data, and estimation of structural behavior and service life. Essential element is to obtain the accurate and many measurements of sensors attached to structural members for estimating reliable structural behavior and avoiding sudden collapse. Although technologies for new type of sensor and data process have been grown, there are still members those are not monitored or exactly estimated. The representative examples are the present prestress force in strand and fastening state of bolt connection. Despite the fact that failure of prestressed strand and bolt may lead a catastrophe by sudden failure, monitoring for them has not been performed fully due to the lack of practical, economic, and quantified ways. In this paper, two sensing systems were introduced. One is anchor head load cell able to measure present prestress force and another is detecting system for the loosening of bolt connection. With these sensing systems, connected members with prestressed tendon or bolt connection can be maintained successfully.

Abstract: Batten plates can play a significant role in reducing the bearing capacity of the entire component and preventing the upward warpage deformation in the opening section. The specific number of batten plates should be calculated for the open cold-formed thin-walled steel structure. By theoretical analysis, this study develops the flexural-torsional buckling formula for the open lipped-channel section cold-formed thin-walled axially compressed members with batten plates. The calculating results show that, according to the configuration rule with 80 iy space between batten plates along the opening direction in the open thin-walled steel members, the warpage deformation will be effectively prevented in the opening direction. Besides, the bearing capacity of the entire member will be increased. The proposed calculation methods can actively complement the existing code.

Abstract: In this article, by studying the horizontal and vertical shear performance, the calculation formula for the fully shear connection is proposed. In order to avoid the overall vertical relative slippage between the steel and concrete, the vertical slippage formula is proposed to calculate the required number of the shear connectors for the first weak plane and second weak plane.

Abstract: Based on the compression characteristics of the concrete-filled thin-walled square steel tube short columns, the U-shaped tie bars are designed in this paper. The U-shaped tie bars and steel pipe walls are connected with each other in T-shape in order to enhance the local stability of the walls under pressure. According to the concrete strength C30/C35/C40 and the thickness of the steel plates 1.25mm/1.75mm/2.5mm,42 short-column specimens are made, and the size of all specimens is 200mm×200mm×690mm.The bearing capacity test is done by the 500-ton electro-hydraulic serve testing machine. The strain of U-shaped tie bar and thin-walled steel are tested, and then the whole curve of compression process is obtained. The results show that the U-shaped tie bar has a very good role in bonding, and has good effects on improving buckling mode and the ductility of the components significantly. Concrete-filled thin-walled square steel tube short column fixed U-shaped tie bar has advantages on stronger post- deformability and more applicable to configuration compared with existing research achievements, and can provide a reference for engineering design.

Abstract: The factors on mechanical anchoring performance of HRB500 steel bars, such as concrete strength, concrete cover thickness, diameter of steel bar, anchorage length of steel bar and transverse reinforcement ratio, were studied based on pull-out tests of 45 specimens. And the formula of mechanical anchoring bond strength for HRB500 steel bars was concluded by statistical regression analysis method. Through the reliability analysis, the mechanical anchoring length of design value and the table of conversion ratio between mechanical and direct anchoring length of HRB500 steel bars have been proposed. So it could be used as a basis for practical projects. The results indicate that the mechanical anchorage length of HRB500 steel bars can be still designed with the formula proposed in GB 50010-2002 “Code for design of concrete structures”.