Current Issue : July - September Volume : 2015 Issue Number : 3 Articles : 6 Articles
Transverse opening in a beam has a reducing effect of the beam stiffness which will cause a significant\nincrease in beam deflection in the region on the opening. In this paper, a new stiffness\nmatrix for a beam element with transverse opening including the effect of shear deformation has\nbeen derived. The strain energy principle is used in the derivation process of the stiffness matrix\nand the fixed-end force vector for the case of a concentrated or a uniformly distributed load is also\nderived. The accuracy of the obtained results based on the derived stiffness matrix is examined\nthrough comparison with that of the finite element method using Abaqus package and a previous\nstudy which show a good agreement with high accuracy....
An anisotropic damage mechanics model is presented to describe the behavior and failure of concrete\nunder biaxial fatigue loading. Utilizing the approach of bounding surfaces, the limit surface\nbecomes a special case when the number of loading cycles is set to one. By increasing the number\nof loading cycles, the strength of concrete gradually decreases and the limit surface is allowed to\ncontract and form new curves representing residual strengths. The magnitude of loading, load\nrange, and the load path are known to influence the fatigue life and hence are addressed in this\nformulation. In this paper, a strength softening function is proposed in order to address the reduction\nin the strength of concrete due to fatigue. Separate softening functions are also proposed\nto account for the deformation characteristics in concrete under cyclic loading. Numerical simulations\npredicted by the model in both uniaxial and biaxial stress paths show a good correlation\nwith the experimental data available in the literature...
This paper compared the rheological properties and compressive strengths of self-compacting\nconcrete (SCC) and conventional cement concrete. The flowability and segregation resistance of\nfreshly mixed concrete specimens were examined by the V-funnel apparatus, while the characteristics\nof passing ability were investigated with the L-box apparatus. Cylindrical concrete specimens\nof 100 mm diameter Ã?â?? 200 mm length were investigated for compressive strength. The\nrheological properties of SCC are incomparable with those of the conventional concrete due to\ntheir diverse testing methods and characteristics of individual flow. The compressive strength results\nof hardened concrete showed that SCC gained strength slowly compared to the conventional\ncement concrete due to the presence of admixtures and its 28 days strength was lower than conventional\ncement concrete, but SCC eventually had potentials of higher strength beyond 90 days.\nFinally, the effect of water-cement ratio on the plastic properties of self-compacting concrete was\nquite negligible compared to conventional concrete....
This study aims to evaluate energy absorption capacity of hysteretic steel damper for earthquake protection of structures.These types\nof steel dampers are fabricated from mild steel plate with different geometrical shapes on the side part, namely, straight, concave,\nand convex shapes. The performance of the proposed device was verified experimentally by a series of tests under increasing inplane\ncyclic load.The overall test results indicated that the proposed steel dampers have similar hysteretic curves, but the specimen\nwith convex-shaped side not only showed stable hysteretic behavior but also showed excellent energy dissipation capabilities and\nductility factor. Furthermore, the load-deformation relation of these steel dampers can be decomposed into three parts, namely,\nskeleton curve, Bauschinger part, and elastic unloading part. The skeleton curve is commonly used to obtain the main parameters,\nwhich describe the behavior of steel damper, namely, yield strength, elastic stiffness, and postyield stiffness ratio. Moreover, the\neffective stiffness, effective damping ratio, cumulative plastic strain energy, and cumulative ductility factor were also derived from\nthe results. Finally, an approximation trilinear hystereticmodel was developed based on skeleton curve obtained fromexperimental\nresults....
The damage which brought about global warming and climate change to heritage sites is more or\nless immutable. However, further deterioration could be slowed, if not stopped, with the patronization\nof green energy. Three sources of green energy, namely solar power, wind power, and hydropower\nwere discussed in this research. Their indirect role in preserving heritage sites was\nexamined and their cumulative effects on mitigating climate change were also cited. Results\nshowed that the climate might have been continually changing for the past thousands of years. The\neffects of climate change and global warming on the arctic ice, carbon dioxide concentration, sea\nlevels, global surface temperature and land ice status were undeniable. These factors greatly contributed\nto the deterioration of the preservation of world heritage sites....
Pakistan is an underdeveloped country, still striving for improvement in construction practices. Most of the private construction\nis carried out as nonengineered which caused loss of approximately 85,000 lives in Kashmir (2005) earthquake. However, after\nthe Kashmir (2005) earthquake, the government and engineering community emphasized on implementation of seismic codes.\nAlthough the current construction practices are considered as better than previous construction work the vulnerability of these\nstructures is yet to be determined. It aims at the vulnerability assessment of recent RC construction in Pakistan that still needs to\nbe assessed. Research work starts with calibration of panel zone element (PERFORM 3D) depicting joint shear degradation, while\ncomparing the analytical results with experimental work, found in the literature. The frame work is then used for vulnerability\nassessment of RC structures typical of current construction practices in Pakistan while using advanced capacity spectrum method,\ndeveloped byKyriakides forwhich three cases have been considered, being constructedmore frequently by public sector, in different\nseismic zones, based on design usually followed by builders in the region. Finally, the conclusion is drawn with suggestion of further\nimprovement of seismic behavior of the structures....
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