Advanced Materials Research Vols. 250-253

Abstract: This research presents some features about juniper timber, above all related with aspects of its structural use (for supports, pillars, beams, roofs...) in some vernacular architecture. Therefore, a special attention is driven to botanical, technical, mechanical features, typical for this type of rare wood. Its traditional use in the Iberian Peninsula and throughout the Mediterranean Basin is still visible in some cases of study, presented in the research. Good constructive qualities make juniper timber a great candidate for further test-researches and experiments, focalized on the family of traditional and”ever green “constructive materials.

Abstract: The feasibility of manufacturing non-autoclaved aerated concrete using alkali activated phosphorus slag as a cementitious material was investigated in this paper. Liquid sodium silicate with various modules (the molar ratio between SiO₂ and Na₂O) was used as alkali activator and a part of phosphorus slag was replaced with fly ash which was used to control the setting time of aerated concrete. The influences of the fly ash, curing procedure, modulus of sodium silicate solution and concentration of alkalis on the compressive strength and bulk density of non-autoclaved aerated concrete have been studied. Moreover, the types of the hydration products were investigated using XRD and SEM. The results indicate that: the compressive strength of aerated concrete was influenced by concentration of alkalis obviously. The compressive strength of 11.9MPa and the bulk density of 806kg/m³ were obtained with an activator of 1.2 modulus of sodium silicate and 6% concentration of alkalis under the circumstance of 60°C curing for 28 days.

Abstract: A study is carried out to develop a Precast Lightweight Foamed Concrete Sandwich Panel, PLFP, as a new and affordable building system. Experimental investigation to study the behaviour of the panel under axial load is undertaken. The panel consists of two lightweight foamed concrete wythes and a polystyrene insulation layer in between the wythes. The concrete panels are reinforced with 9mm diameter high tensile steel bars. The rebars are tied to each other through the insulation layer by shear connectors which are made of 6mm mild steel bars bent to 45º angle. Total number of four specimens was tested with one specimen; PA1 was cast without capping at both ends. It was used as a pilot test. The other three specimens are capped with normal concrete at both ends to avoid end crushing during axial loading. Axial load test was conducted and the results are presented here, which include the ultimate load capacity, crack pattern and failure mode, strain distribution and load-deflection curve of the panels. The experimental ultimate strength achieved recorded lesser percentage difference with the formulae by Pillai and Parthasarathy when compared to formulae in BS8110. It is also observed that the strength of the panels are affected by the compressive strength of the foamed concrete forming the wythes, the presence of concrete capping at panel’s ends and the slenderness ratio, H/t. Specimens with capping at both ends recorded higher ultimate loads with no premature crushing. Failure of panels with slenderness ratio, H/t < 18 were by premature buckling near the supports whereas for panels with higher H/t ratio, slight bending was observed in the middle zone. The results also indicate that a certain degree of compositeness is achieved between the wythes.

Abstract: In the study, in order to enhance the durability and constructability of the pile foundation, hybrid FRP-concrete composite pile is developed and its applicability considering construction is discussed. Existing FRP-concrete composite pile is consisted of concrete pile and filament winding FRP wound outside of the pile. To improve the axial and transverse load carrying capacities longitudinal reinforcement is also needed additionally, and hence a new type hybrid FRP-concrete composite pile (HCFFT) is suggested. A new type HCFFT which is composed of pultruded FRP, filament winding FRP, and concrete filled inside of the FRP tube is proposed to improve compressive strength as well as flexural strength of the HCFFT pile. The load carrying capacity of proposed HCFFT pile is evaluated and discussed based on the result of experimental and theoretical investigations.

Abstract: This thesis analyzes the exhaust system of residential kitchen existing problems of indoor air quality. Discusses how to making up air to balance indoor air, eliminate the traditional system defects, through in the hearth additional secondary air tuyere through using the CFD----fluent6.2 simulation software simulates the airflow organization of the kitchen exhaust system if making up air . Analyze the kitchen indoor airflow velocity distribution, and the pressure distribution and velocity vector in the different condition. Under the action of differential pressure, outdoor air is sucked into the kitchen so as to achieve the reasonably airflow organization and get rid of foul gas effectively.

Abstract: The paper makes an analysis of the selected location and feasibility of the exposure test ground in the real marine environment, and the endurance test of the FRP- reinforced concrete built-up beam has been carried out on the exposure test ground. After 6 month and 12 month’s exposure test, the beams' mechanic performance and the chloride ion content in different depths have been determined. The results show that after the exposure test, the beams' ultimate capacity has been greatly decreased to a certain extent, and the FRP board can effectively prevent chloride from penetrating.

Abstract: The paper probes into the application of masonry strengthening with mortar splint in the reinforced masonry structure. By optimizing the reinforcement scheme, computing and comparing the indexes of the compound seismic capacity of the building before and after it is strengthened, it can be concluded that the method of masonry strengthening with mortar splint can greatly improve the compound seismic capacity of buildings and achieve the goal of building’s strengthening.

Abstract: The main object of this paper is to apply the vector form intrinsic finite element (VFIFE, or V-5) techniques in nonlinear large deformation dynamic analysis for the responses of moving loads on rigid frame structures. In this study, the simulation of moving loading is brought into the vector form intrinsic finite element method. It can effectively simulate the moving load. Comparing the results of the numerical simulations by VFIFE with the results obtained from other literatures, they are very close. It proved that VFIFE can effectively simulate the nonlinear large deformation dynamic problem.

Abstract: During the construction of the deep-buried tunnels, high surrounding rock stress and the rockburst are the important factors affecting the stability of surrounding rock. Xiabandi hydraulic engineering is the key project in Tarim River basin. Due to the deep buried excavation, rockburst is particularly prominent and should be received adequate attention. According to the rockburst practice during construction, numerical analysis is adopted to study the stress characteristics along depth with the same lateral pressure coefficient. Furthermore, the rockburst tendency along the tunnel with different burying depth is investigated. The conclusion is of great value to guide the rockburst control during the tunnel design and construction.

Abstract: Rowlock cavity wall was widely used in rural house in Southern Jiangsu Province from 1980s to 1990s. As one type of masonry structures, the seismic performance of rowlock cavity wall has rarely been studied on. Based on the report of General Seismic Investigation in Jiangsu Qidong, one 1/2-scale rowlock cavity wall structure was modeled as the existing rural house, and was tested on shaking table in lab of Southeast University. After analyzing the failure state of the model, and examining the structural parameters such as natural frequency, damping ratio, floor acceleration, floor shift, strain and crack of the model in load condition of different earthquake wave and intensity, the seismic performance of rowlock wall structure was assessed. And the seismic capacity of the whole model and each piece of rowlock wall was also analyzed. Based on the mortar strength field inspected in model wall, the seismic capacity of model structure under the action of rarely occurred earthquake of level 6 seismic precautionary intensity was estimated. The result showed that the model structure would collapse under the load condition. Obviously, this can not satisfy the seismic precautionary requirement in Code for Seismic Design of Buildings (GB50011-2001). Therefore, some principal reinforcement suggestions were discussed and proposed for existing rowlock cavity wall buildings. The research result of this paper could provide some theoretical foundation for the Aseismic Residential Project of rural peasant house, and also could be referred to for further research on rowlock cavity wall structures.