Application Of Sustainable Design Principles To Increase Energy Efficiency Of Existing Buildings

This study investigates the effectiveness of different energy retrofitting techniques and examines the impact of employing those methods on energy consumption of existing residential buildings. Based on the research findings, the most effective and practical method of retrofitting has been proposed in order to improve energy efficiency of existing buildings. In order to achieve this goal, an existing residential building has been simulated in FirstRate 5 software so as to determine the existing thermal performance of the building. Afterwards, considering sustainable design principles, different insulation layers, glazing, and construction materials have been employed to conduct a comprehensive thermal performance study. Based on the research outcomes, the best technique for increasing energy efficiency of existing buildings and reducing their environmental impact and footprint has been identified and proposed for practical purposes

A CRITERION FOR CONSIDERING SOIL-STRUCTURE INTERACTION EFFECTS IN SEISMIC DESIGN OF DUCTILE RC-MRFs ACCORDING TO IRANIAN CODES

During the last quarter of the 20th century, the importance of dynamic soil-structure interaction for several structures founded on soft soils was well recognized. If not accounted for in analysis, the accuracy in assessing structural safety in the face of earthquakes cannot be accounted for adequately. For this reason, seismic soil-structure interaction analysis has become a major topic in earthquake engineering. As the Iranian Code of Practice for Seismic Resistant Design of Buildings (Standard No. 2800-05) does not address the soil-structure interaction explicitly, the effects of such interaction on behavior of reinforced concrete buildings with ductile moment-resisting frames, loaded and designed according to the Iranian Building Codes, are studied in this research, using direct soil-structure interaction method. To achieve this objective, four types of structures consisting of 3, 5, 7 and 10 story buildings, which represent the typical buildings in a high risk earthquake prone zone, have been selected in conjunction with three types of soil, representing types II, III and IV, as classified in the Iranian Standard No. 2800-05. Ductile Reinforced Concrete Moment-Resisting Frames, as fixed-base structures, once without soil interaction and the next time considering their soil interaction by direct method are modeled and subjected to different earthquake records. The results of the two cases subjected each to different earthquake records are studied and compared. This Comparison led to a criterion indicate that consideration of soil-structure interaction for seismic design, in buildings higher than three stories on soil type IV (Vs<175 m/s) as well as buildings higher than seven stories on soil type III (175<Vs<375 m/s), is essential

Shaking Table Tests on Soil-Structure System to Determine Lateral Seismic Response of Buildings

In this study, a series of experimental shaking table tests were performed on a physical fixed based model (structure directly fixed on top of the shaking table) and a flexible base model (soil-structure system) under the influence of four scaled earthquake acceleration records (two near field and two far field records) and the results were measured. The soil-structure system includes a 15 storey structural model resting on a synthetic clayey soil mixture consisting of kaolinite, bentonite, class F fly ash, lime, and water. The selected soil model was placed into a laminar soil container, designed and constructed to realistically simulate the free field conditions in shaking table tests. Comparing the measured response of fixed base and flexible base models, it is noted that the lateral deflections of flexible base model have evidently amplified in comparison to the fixed base model. As a result, performance level of the structural model may change extensively (e.g. from life safe to near collapse level), which may be extremely dangerous and safety threatening. Thus, it is experimentally observed that dynamic soil-structure interaction plays a significant role in seismic behaviour of moment resisting building frames resting on relatively soft soil

Experimental Investigations on Behaviour of Steel Structure Buildings

In this study, a comprehensive procedure for design, building and commissioning of scale steel structure building models has been developed and presented for practical applications in shaking table test programmes. To validate the model, shaking table tests and numerical time history dynamic analyses were performed under the influence of different scaled earthquake acceleration records. Comparing the numerical predictions and experimental values of maximum lateral displacements, it became apparent that the numerical predictions and laboratory measurements are in a good agreement. As a result, the scale structural model can replicate the behaviour of real steel structure buildings with acceptable accuracy. It is concluded that the physical model is a valid and qualified model which can be employed for experimental shaking table tests

Effects of Dynamic Soil-Structure Interaction on Performance Level of Moment Resisting Buildings Resting on Different Types of Soil

In this study, two structural models comprising five and fifteen storey moment resisting building frames are selected in conjunction with three different soil deposits with shear wave velocity less than 600m/s. The design sections are defined after applying dynamic nonlinear time history analysis based on inelastic design procedure using elastic-perfectly plastic behaviour of structural elements. These frames are modelled and analysed employing Finite Difference approach using FLAC 2D software under two different boundary conditions namely fixed-base (no soil-structure interaction), and considering soil-structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted and the results of inelastic behaviour of the structural models are compared. The results indicate that the inter-storey drifts of the structural models resting on soil types De and Ee (according to the Australian standard) substantially increase when soil-structure interaction is considered for the above mentioned soil types. Performance levels of the structures change from life safe to near collapse when dynamic soil-structure interaction is incorporated. Therefore, the conventional inelastic design procedure excluding SSI is no longer adequate to guarantee the structural safety for the building frames resting on soft soil deposits

Effects of Dynamic Soil-Structure Interaction on Inelastic Behaviour of Mid-Rise Moment Resisting Buildings on Soft Soils

In this study, a ten storey moment resisting building frame, representing the conventional type of regular mid-rise building frames, resting on shallow foundation, is selected in conjunction with a clayey soil, representing subsoil class Ee, as classified in the AS 1170.4. The structural sections are designed after applying dynamic nonlinear time history analysis, based on both elastic method, and inelastic procedure using elastic-perfectly plastic behaviour of structural elements. The frame sections are modelled and analysed, employing Finite Difference Method using FLAC 2D software under two different boundary conditions: (i) fixed-base (no Soil-Structure Interaction), and (ii) considering Soil-Structure Interaction (SSI). Fully nonlinear dynamic analysis under influence of different earthquake records is conducted and the results of the two different cases for elastic and inelastic behaviour of the structural model are extracted and compared respectively. The results indicate that the lateral deflection increments for both cases are substantially dominating and can change the performance level of the structures from life safe to near collapse or total collapse. Therefore, conventional elastic and inelastic structural analysis methods assuming fixed-base structure may no longer be adequate to guarantee the structural safety. Therefore, considering SSI effects in seismic design of concrete moment resisting building frames resting on soft soil deposit is essential

Effects of soil-pile-structure interaction on seismic response of moment resisting buildings on soft soil

Dynamic response of structures sitting on soft soils is influenced by the soil properties, and the response is significantly different to the fixed base condition owing to the interaction between the ground and the structure, In order to study this effect, a fifteen storey moment resisting building frame, representing a conventional type of regular mid-rise building frame, resting ,on soil type Ee according to Australian Earthquake action code with the shear wave velocity equal to 150 mls is adopted. The numerical analysis using FLAC2D software is carried out for three different cases, namely: (1) fixed-base structure representing the situation excluding the soil-structure interaction (SSI); (2) structure supported by shallow foundation on soft soil; and (3) structure supported by pile foundation in soft soil. Benchmark earthquakes including the 1995 Kobe, the 1994 Northridge, the 1968 Hachinohe, and the 1940 EI Centro earthquakes are adopted. Results indicate that considering soil-structure interaction in both cases with shallow and pile fouudations is vital, and the conventional desigu procedure excluding soil-structure interaction is not adequate to guarantee the structural safety for the moment resisting buildings resting on the soft soil

Significance of bedrock depth in dynamic soil-structure interaction analysis for moment resisting frames

In this study, a fifteen storey moment resisting building frame, resting on a shallow foundation, is selected in conjunction with two clayey soils with the shear wave velocities less than 600m/s, representing soil classes De and Ee, according to AS 1170.4. Different bedrock depths including 10m, 20m, and 30 m are employed in the numerical modelling using finite difference software FLAC 2D. Fully nonlinear dynamic analysis under the influence of different earthquake records is conducted, and the results of the three different cases are compared and discussed. The results indicate that the dynamic properties of the subsoil such as shear wave velocity as well as bedrock depth play significant roles in seismic response of the building frames under the influence of soil-structure interaction. As the bedrock depth increases, lateral deflections and inter-storey drifts of the structures increase. These effects can change the performance level of structures from life safe to near collapse or total collapse. Therefore, the conventional design procedure excluding SSI is not adequate enough to guarantee the structural safety for the building frames resting on soft soil deposits

Ionic regulation ability in Rutilus frisii kutum fingerlings during sea water adaptation.

Experiments were conducted to determine the effects of weight on the ionic regulation ability of reared Rutilus frisii kutum fingerlings during adaptation to the seawater and downstream migration. Accordingly, the ionic regulation ability of Cl-, K+, Na+ and Mg2+ in kutum fingerlings with weights of 1, 3, 5 and 7 g in three different salinities, that is 13‰ (the Caspian Sea salinity), 7‰ (estuarine area) and fresh water (as control, 0.3-0.5‰), were assessed. The blood samples were provided before being transferred as control (fresh water) and during adaptation to the sea and estuary water in a period of up to 336 h by a pooling method. The measurements of ions were carried out for blood serum Na+ and K+ and alsoplasma Cl-1 and Mg2+ by photometric methods. This investigation showed that ionic regulatory ability of kutum fingerlings depends on their weights. Results of ionic changes during the duration of 336 h (14 days) proved that unlike kutum fingerling with weights of 3, 5 and 7 g, the ionic regulation system in 1 g fingerlings were not able to expel excess ions. Further 1 g kutum were not physiologically ready (smolt) for downstream migration

Long-term structural behaviour of composite sandwich panels

© Avestia Publishing, 2017. New materials are great additions to the structural world dominated by concrete and steel creating sustainable products and low impact materials that can go head to head with concrete and steel. The new materials being discovered can often outperform traditional materials and have added benefits that improve the in-life performance such as thermal capabilities and sound insulation. One of these construction materials are sandwich panels made of two materials that are relatively weak in their separated state, but are improved when they are constructed together in a sandwich panel. Sandwich panels can be used for almost any section of a building. Polystyrene/cement mixed core and thin cement sheet facings sandwich panels are Australian products made of cement-polystyrene beaded mixture encapsulated between two thick cement board sheets. Long-term structural behaviour of these sandwich panels are relatively unknown. Therefore, in this study, in order to understand the creep and creep recovery behaviour and properties of those sandwich panels, a series of experimental tests have been performed and the outcomes have been explained and discussed. Based on the results of this study, values for immediate recovery, creep recovery and irrecoverable creep strain are determined and proposed. In addition, typical creep and creep recovery design charts have been developed and presented for practical applications in structural engineering