Applied Mechanics and Materials Vol. 147

Abstract: The earth building is a building type with enormous quantity and widely being used in rural section of south-western part. It will dominate for a long time. The environment of traditional earth buildings is very poor because of out-dated ideological limitations and construction mode, it can’t meet the needs of increasingly demanding of local people. So these buildings must recur to modern technologies to integrate fine parts in tradition and form new appropriate technologies. This paper took Yi minority’s houses in Yongren as an example to look for a road opening to rural buildings’ sustainable development.

Abstract: The fundamental approach for solving the durability deficiency is to perform the durability design for planned concrete bridges and the durability maintenance for existing concrete bridges. Most of the existing durability design and maintenance methods, however, are qualitative and contain many subjective factors, which cannot solve the problems such as whether the structure is safe or not throughout the service life. The critical problems, such as the design service life, the environmental parameters, the material degradation process, as well as the lifetime performance assessment method, are found out based on deep insight into the existing concrete bridge durability design and maintenance methods. Finally, the schematics of concrete bridge durability design and maintenance methods that can quantitatively evaluate the degradation process of concrete bridges are proposed and the further research direction is determined.

Abstract: The Iron Bridge completed in 1779 was the world’s first bridge. It is located at the world heritage site of Ironbridge Gorge in Shropshire, England. In order to predict the stress distribution and deformation in the bridge, the Iron Bridge was modelled and analysed using the finite element method. The maximum tensile stress was predicted to occur in the strut close to the middle of the bridge, which could be the reason why the strut failed. The numerically predicted deformations in the circles and ogees in the Iron Bridge are in agreement with the observed deformations. It is concluded that for the conservation and maintenance of the historic Iron Bridge, modern numerical simulations are invaluable for providing guidance.

Abstract: Sleeved purlin systems are usually used in roof constructions. A non-linear relationship between the bolt hole extension and the load transferred to the bolt was derived with experimental testing and numerical simulation. Consequently, the non-linear rotational stiffness of sleeved joints was derived based on the configuration of sleeves in this paper. The procedure for calculating the deflection of purlin systems with non-linear rotational stiffness at the joints is presented. The analysis and calculation of the deflection is demonstrated through a case study.

Abstract: The aim of this study is to propose two numerical models by a well-known soft computing method, Genetic Programming (GP), for the estimation of soils compaction parameters. Genetic Programming is a pattern recognition approach that has the ability of modeling the non-linear behavior of complex engineering problems. The input variables were the soil classification properties, and the outputs were the Optimum Moisture Content (OMC) and Maximum Dry Density (MDD). To provide model, a database including properties of different soils classified as CH, CI, CL, GC, GM, MH, MI, ML and SC was used. In addition, a new Multiple Linear Regression (MLR) based formula using the database, compared with the GP based model. Study results revealed that the proposed formula by GP can predict the compaction parameters of soils in a highly precise manner, and its outputs were in satisfactory conformity with real test results. Performances of the proposed models evaluated using the regression statistical analyses. The proposed formulae can be useful for the preliminary design of engineering projects and are more useful for cases with time and financial limitations.

Abstract: In the past few decades, the use of spur dikes for stability of the outer banks of rivers has attracted the attention of hydraulic engineers. Setting spur dikes in the flow’s direction leads to local scour around the spur dike and changes the topography of the bed. This paper deals with the study of the temporal variation of the scour hole and topography of the bed around a T shaped spur dike located in a 90 degree bend. The experiments were carried out in a channel with a 90 degrees bend. Uniform sediments having an average diameter of 1.28mm were used under clear water condition. The effects of Froude number on the amount and the geometry of scour hole around a T shaped spur dike and the time variation of scour were investigated.

Abstract: Experimental and numerical studies conducted in the past three decades have demonstrated that a steel plate shear wall is an effective and economical lateral load resisting system against both wind and earthquake forces. The system consists of infill steel plates connected to boundary beams and columns over the full height of the framed bay. The infill plates can be stiffened or unstiffened and the beam-to-column connections can be rigid or shear connections. A properly designed steel plate shear wall has superior ductility, high initial stiffness, stable hysteresis loops, and good energy absorption capacity. These characteristics make the system outstanding in high-risk seismic regions. Use of steel plate shear wall systems has been shown to be more cost effective than the other lateral load resisting systems. Steel plate shear walls are much lighter than the commonly used reinforced concrete shear walls, which reduce both the gravity loads and seismic forces. This aspect significantly reduces the foundation costs and makes the system outstanding for application in rehabilitation projects. Whereas construction cost of stiffened steel plate shear wall is more than unstiffened steel plate shear wall therefore in this investigation the unstiffened steel plate shear wall has been studied as two types of simple and corrugated plate and the behavior has been compared in one story frame. This study was conducted with finite element approach theoretically. The results of this study demonstrated that behavior of corrugated plate is superior to simple plate because it has high loading capacity, ductility and energy absorption.

Abstract: A tie beam in a pier is demaged owing to the collapse of the bridge girder erection machine in the construction. In order to evaluate the safety of the pier stud, the effect of force induced by the impact of the collapse is analyzed. The results show that the concrete in bottom of the pier is compressed and that the tensile stress of concrete in the root of the damaged tie beam is less that the designed tensile strength of the concrte. The analyzed results are in line with the real state of the damaged tie beam.

Abstract: External bonding of fiber reinforced polymer (FRP) sheets to concrete is a popular method of strengthening reinforced concrete (RC) structures. A simple test was set-up in order to simulate the process of debonding in this type of strengthening. The set-up is simulating the bond behavior of strengthened RC structures. In the recent researches it was found out that bond behavior and actual stress distribution is a 3 dimensional phenomenon. This paper is presenting more details about pull-off tests by applying 3-D and nonlinear finite element models. As a first step linear model has been generated to show general stress distribution in the test, in a second step nonlinear model is implemented in order to predict the behavior of pull-off tests more accurately. Tests have shown that at ultimate load, deboning occurs within a concrete layer near the bond surface. Therefore, the paper is focusing on using a more realistic concretebehavior in the model.

Abstract: Experiments on square and circular steel columns filled with light-weight concrete and high strength concrete have been conducted to investigate the contribution of these types of concrete to load bearing capacity of short composite columns. The aim of this research was to determine the effect of two types of concrete filling on behaviour of the composite columns. Thirteen specimens were divided in two groups: steel tubes filled with different type of concrete, with or without reinforcement and RC columns with same dimensions and shape, made of same type of concrete. Comparison was made between load bearing capacity of the steel tubes filled with light-weight concrete, and high strength concrete (with and without reinforcement). All specimens were tested by axial compression until to the failure state realization. Factors which influence the behavior and failure mode, ultimate strength, deflections and stress-strain relation were discussed.