Applied Mechanics and Materials Vols. 94-96

Abstract: Abstract: Taking a Practical Big Span Stadium Project as the Background, in View of its Particularity that it Suffered Earthquake Damage and Fortification Intensity Increased after Earthquake, through the Field Detection and Finite Element Model to Analyze Earthquake Damage of Structure Caused by Wenchuan Earthquake, and Research the Feasibility of Seismic Strengthening with Hadas on the Structure Whose Fortification Intensity Increased after Earthquake. the Results Show that: 1) the Big Span Structure Severely Damage by the Earthquake, the Second Layer Is Relatively Weak Layer, Prone to Local Damage and Affect Whole Anti-seismic Performance of Structure, 2) Hadas Can Increase the Initial Stiffness and Effectively Reduce the Structure Seismic Response, Has Better Effect on Overall Reinforcement, 3) it Is Reasonable to Improve the Seismic Fortification Intensity of this Region.

Abstract: This paper studies seismic behavior of concrete-filled square steel tubular column-to-beam connection with through diaphragm, which is popular in Japan, but rarely used in China. Four full-scale cruciform specimens are tested under low-cyclic reversed load and the result of study indicates that diaphragm-through joints have stable hysteretic characteristics and enough energy dissipation capacities to be used in the field. Details of the steel beam flange connecting with the diaphragm have obvious effects on joint ductility and energy dissipation, and the seismic behavior of joints with circular fillet at the connecting zone are better than that reinforced by taper plate welded to the beam flanges. For the specimens failed in the beam, diaphragm thickness, size of concrete cast holes, width-to-thickness ratio of the tube, and the level of axial load in the column have less influence on joint seismic behavior.

Abstract: The internal relative humidities of concrete using different types of ceramsites with different prewetting degrees were monitored by humidity sensors. The study reveals that the internal relative humidity of concrete using low water absorption rate ceramsites declines more slowly than that of concrete using high water absorption rate ceramsites when not prewetting; the internal relative humidity of concrete using high water absorption rate ceramsites is higher than that of concrete using low water absorption rate ceramsites when their prewetting degrees (1h or 24h) are the same; the internal relative humidity of concrete using ceramsites is higher than that of ordinary concrete, whether the ceramsites are prewetted or not.

Abstract: Abstract. Size effect, referring to mechanical properties of materials change with the geometry changes, is the basic characteristic of brittle and quasi-brittle materials. Researches show that for the concrete material, compressive strength, split tensile strength and tensile strength decrease with the size of components increases, for RC structures, size effect also exists. The development and current situation in size effect are presented from three aspects, including concrete, RC members and the application of the code. And then, the developing trends of size effect of RC members are proposed.

Abstract: The positioning measurement of spatial curved surface steel structure project is a key link in construction process. How to measure position fast and precisely is an important problem concerned by steel structure project field. Taking actual project as an example, this article studied precision construction measurement technology in curved surface steel structure project, put forward resemble-leveling method elevation measurement, and naturalization lofting method which is based on spatial linear equation. This article has important guiding significance to precise position measurement of curved surface steel structure project and to construction control.

Abstract: In the actual project, many concrete structures not only suffer the loading of static force and the repeated loading but also affected by the corrosive effects of chemical substances in external environment, which makes concrete corrosion and damage become an unavoidable issue in engineering. The research on it at home and abroad is still in stage of theoretical exploration. This paper studied the attenuation of the residual strength of concrete under fatigue loading and corrosion of chloride, using self-designed experimental corrosion fatigue loading device. The results show that the corrosion of concrete by chlorine ion is unneglected, its influence is greater than mathematical superposition of alternating load and corrosion when they affect the concrete separately.

Abstract: 2008 Wenchuan earthquake has showed that failure of masonry walls is one of the major causes of material damage and loss of human life due to seismic events. Therefore, study of masonry walls seismic behavior and development of effective and practical retrofitting schemes is an urgent need. So this work presents an experimental program that investigates in-plane seismic behavior of common types of shale masonry walls before and after retrofitting using epoxy resin injection technique. In this experimental study, the primary objective was to evaluate the efficiency of this retrofitting method on masonry walls. The results of this study shows that using epoxy resin injection technique increased the in-plane maximum strength, the ductility, the initial stiffness value, the stiffness, and the energy dissipated during all the loading stages, and decreased the ductility factor.

Abstract: According to the climate feature and the energy-saving requirements of traditional residential in hot- summer and cold -winter zone in china, we proposed the transformation scheme for the external structure of residential. The main points of the appropriate technical measures for the project also have illustrated clearly.

Abstract: The layer structure is a common structural form in the civil air defence. According to the shortage of the structure, a new type of structural form called steel fiber sheet sandwich structure is setup. For studying the influence caused by the support span of this structural form on structural blast-resistant ability, this paper has carried out a group of explosion model tests, which studies the optimal support span of this structure form and the influence on the failure characteristics of structure induced by the change of the support span. The test results show that: the support span of the steel fiber sheet is a very important factor for improving the whole structural blast-resistant ability; the thickness and support span of Steel fiber sheet shall make the steel fiber sheet not to reach the roof surface under the loads of explosion; the whole resistance of sheet sandwich structure in the tests is obviously higher than that of ordinary layer structure.

Abstract: Abstract: Nowadays, a huge amount of concrete has been used as main construction material. This as a consequence will consume a large quantity of natural aggregates which quantity is not limitless. On the other hand, for instance, in the tunnel construction, a lot of spoil rocks could be produced. It will be beneficial both from the aspect of economy and ecology if these spoil rocks could be used as concrete aggregates. In this case, the alkali reactivity of the spoil aggregates will have to be determined to avoid the potential reaction between aggregates and cement. In this contribution, the spoil aggregates from Qingdao Jiaozhou Bay Subsea Tunnel have been used to prepared concrete specimens. And their alkali reactivity has been determined by swelling test. The results indicate that the swelling rates of all specimens made by spoil aggregates, both from 6 different places in underground part and from 13 places in subsea part of the Tunnel, are at most 0.08 %, which is not higher than the limit value of 0.1 % according to the standard. This means the tested spoil aggregates do not have potential alkali reactivity, and they can be used as concrete aggregates.