Current Issue : April - June Volume : 2020 Issue Number : 2 Articles : 5 Articles
A study concerning the performance assessment and enhanced retrofit of public buildings\noriginally designed without any anti-seismic provisions is presented herein. Arepresentative structure\nbelonging to this class was demonstratively examined, i.e., a school built in Italy in the early 1970s,\nbefore a coordinate national Seismic Standard was issued. The building is characterized by a mixed\nreinforced concrete (ground storey)-steel (first and second storey) frame skeleton. An extensive\non-site experimental investigation was developed in the first step of the study, which helped identify\nthe mechanical characteristics of the constituting materials, and re-draw the main structural details.\nBased on these data, and relevant updates of the finite element model of the structure, the seismic\nassessment analyses carried out in current conditions highlighted several performance deficiencies,\nin both the reinforced concrete and steel members. An advanced seismic retrofit hypothesis of the\nbuilding was then designed, consisting of the installation of a set of dissipative braces incorporating\nfluid viscous dampers as protective devices. This solution makes it possible to attain an elastic\nstructural response up to the maximum considered normative earthquake level, while at the same\ntime causing more limited architectural intrusion and lower costs as compared to conventional\nrehabilitation strategies....
The number of constructed tunnels has been gradually increasing for the past decades due to rapid development in urban areas.\nHowever, the soil-structure interaction problems arising from perpendicularly crossing tunnels attract relatively little research\nattention in the past. In this study, six three-dimensional finite element analyses were conducted to simulate tunnel excavation\nnearby a perpendicularly crossing existing tunnel, in an attempt to investigate the effects of construction sequences on crosscutting\ntunnels. The hypoplastic constitutive model for sand is adopted in the numerical analysis to consider the soil small-strain\nstiffness. Computed results are presented and discussed in terms of ground surface settlement, displacement and deformation of\nthe existing tunnel, and bending moment induced on the existing tunnel.The stress-transfer mechanism in soil nearby the existing\ntunnel due to tunnelling is also studied....
The rational use of energy has motivated research on improving the energy efficiency of\nbuildings, which are responsible for a large share of world consumption. A strategy to achieve this\ngoal is the application of optimized thermal insulation on a building envelope to avoid thermal\nexchanges with the external environment, reducing the use of heating, ventilation and airconditioning\n(HVAC) systems. In order to contribute to the best choice of insulation applied to an\nindustrial shed roof, this study aims to provide an optimization tool to assist this process. Beyond\nthe thermal comfort and cost of the insulation, some hygrothermic properties also have been\nanalysed to obtain the best insulation option. To implement this optimization technique, several\nthermo-energetic simulations of an industrial shed were performed using the Domus software,\napplying 4 types of insulation material (polyurethane, expanded polystyrene, rockwool and glass\nwool) on the roof. Ten thicknesses ranging from 0.5 cm to 5 cm were considered, with the purpose\nof obtaining different thermal comfort indexes (PPD, predicted percentage dissatisfied). Posteriorly,\nthe best insulation ranking has been obtained from the weights assigned to the parameters in the\nobjective function, using the technique of the genetic algorithm (GA) applied to multi-criteria\nselection. The optimization results showed that polyurethane (PU) insulation, applied with a\nthickness of 1 cm was the best option for the roof, considering the building functional parameters,\noccupant metabolic activity, clothing insulation and climate conditions. On the other hand, when\nthe Brazilian standard was utilized, rock wool (2 cm) was considered the best choice....
This paper investigates the possibility of applying novel microwave sensors for crack\ndetection in reinforced concrete structures. Initially, a microstrip patch antenna with a split\nring resonator (SRR) structure was designed, simulated and fabricated. To evaluate the sensorâ??s\nperformance, a series of structural tests were carried out and the sensor responses were monitored.\nFour reinforced concrete (RC) beam specimens, designed according to the European Standards, were\ntested under three-point bending. The load was applied incrementally to the beams and the static\nresponses were monitored via the use of a load cell, displacement transducers and crack width gauges\n(Demec studs). In parallel, signal readings from the microwave sensors, which were employed prior\nto the casting of the concrete and located along the neutral axis at the mid-span of the beam, were\nrecorded at various load increments. The microwave measurements were analysed and compared\nwith those from crack width gauges. A strong linear relationship between the crack propagation\nand the electromagnetic signal across the full captured spectrum was found, demonstrating the\ntechniqueâ??s capability and its potential for further research, offering a reliable, low-cost option for\nstructural health monitoring (SHM)....
The study area is located within the western part of Iraq between Latitude\n(32Degree45'0'' - 34Degree0'0'') North and longitude (39Degree30'0'' - 40Degree45'0'') East within\nAnbar Governorate. It covers an area of 4767.423 Km2 with elevation ranges\nfrom 360 to 840 m. The general slope decreases from southwest to northeast.\nFive old dams identified in the study area. The results of SWAT model\nshowed high curve number (70 - 85) indicating low filtration and runoff rate\n(1.2 - 8.2) mm for the period (1994-2014). These dams have catchment areas\nranged between (118.03 - 673.41) km2. They were to be used for agricultural\npurposes. The results according to the Food, Agriculture Organization (FAO)\nstandards for their distance from agricultural areas using a GIS showed that\nall are not suitable except dam number (1). The distance to roads showed that\ndams (1, 4) are highly suitable, (2, 3) are low suitable and dam (5) is not suitable.\nThe average annual quantity of rain water that can be harvested from\nthe 5 dams is about 12.9 million cubic meters....
Loading....