Journal of the Structural Engineering and Geotechnics
Volume:10 Issue: 2, Summer and Autumn 2020

Abnormal loads due to natural events, implementation errors and some other issues can lead to occurrence of progressive collapse in structures. Most of the past researches consist of 2- Dimensional (2D) models of steel frames without consideration of the floor system effects, which reduces the accuracy of the modeling. While employing a 3-Dimensional (3D) model and modeling the concrete slab system for the floors have a crucial role in the progressive collapse evaluation. In this research, a 3D finite element model of a 5-story steel building is modeled by the ABAQUS software once with modeling the slabs, and the next time without considering them. Then, the progressive collapse potential is evaluated. The results of the analyses indicate that the lack of the consideration of the slabs during the analyses, can lead to inaccuracy in assessing the progressive failure potential of the structure. The results show that a structure is subjected to unusual external loads such as a motor vehicle collision, explosion of a bomb in a vehicle, etc., the most critical columns are located in the nearest frame to the outer frame in the structure.

Golsar is located in north-west of Rasht the capital city of Guilan province. This region, according to standards 2800, is identified among the regions with relatively high risk of earthquake. A set of historical and instrumental seismicity data used in radius of 200 km which covers the period twelveth century until now. Kijko method has been applied for estimating for parameters considering of the available information. Estimating the peak ground acceleration on Bedrock (PGA) with five different attenuation relationship, with a probability of occurrence of 10% in 50 years, is 0.31g in Galsar Rasht region. Meanwhile in order to determine the seismic spectra based on weighed attenuation spectral relations, and also for the reason of being spectral and more suitable with the condition of the zone were used. The horizontal spectral acceleration in the 0.3 second period has the highest value for 2% and 10% probability of occurrence. The earthquake hazard in Golsar zone was calculated using SEISRISK III (1987) software.

The purpose of this research was to evaluate the nonlinear dynamic response of rigid and semi-rigid steel frames under Far-Fault Earthquake Records. Accordingly, the fragility curve of the moment frames with rigid and semi-rigid connections was determined. Considering the analytical knowledge of structures in the past, the analysis and design of steel frames based on the assumptions of rigid or joint connections. While laboratory studies show that most connections are semi-rigid and due to the importance of connections in the structures, it is very important to recognize and accurately study their behavior, especially during an earthquake, and their design must be under their real structural behavior. For this purpose, three two-dimensional steel moment frame structures with 6, 12, and 18 stories were used, which represent short, medium, and high structures. Considering the rigid and semi-rigid connections, their seismic performance was investigated using the nonlinear dynamic incremental analysis (IDA). Three cases of connections have been selected corresponding to 50, 60, and 70% rigidity. Finally, the collapse fragility curve parameters obtained and compared. According to the obtained results, decreasing the rigidity of the beam-to-column connections increases the dispersion of the collapse fragility curve. Besides, it was observed that considering the semi-rigid connections leads to a reduction of the median of the collapse fragility curve. The result shows that the mentioned difference cannot be neglected.

While the existing structures, even recently constructed ones are subjected to the critical earthquakes, the catastrophic devastations are expected to occur. Therefore, at least for several important structures such as power plants, infrastructure, and buildings, there is a need to consider the critical excitation analysis. One of the important criteria in the seismic design of the structures using the criteria in critical excitation is to control the maximum amount of structural displacement. However, the required characteristics of the analysis and design of the structures are generally random variables and have many uncertainties. Therefore, the probability-based analysis should be accomplished to determine the most probable structural responses. The main objective of this research is to investigate the reliability level of buildings subjected to the critical excitations for concerning the steel structures. In due course, the wide range of the SDOF structures is investigated subjected to real ground motions of the critical excitations. Eventually, the reliability index for structures is given in terms were divulged.

In this research, the features of LEED, BREEAM, and NBRI also, their principles, are reviewed, evaluated, and compared from the aspects of the sustainability. The compliance items of standards with the principles of sustainability determine that their goals are well matched. By comparing the different and shared principles, it discovered how each standard has succeeded from the aspect of the sustainable design also, the shortcomings in the 19th issue of NBRI were appeared. The evaluation of standards with sustainability principles is done by applying (MCDM) TOPSIS. furthermore, by ranking each sub-item of standards from weak to excellent, the respect of sustainability principle is recognized. plus, according to the TOPSIS and analyzing the data, any items of each standard has the most sustainability feature are considered. The alignment with the leading tools can result in the promotion of the Iranian regulations. Findings of this research provide suggestions for completing and localizing the criteria that are part of the LEED and BREEAM in energy section which are neglected in the 19th issue. Applying these solutions and paying more attention to all of building's sustainable aspects in Iran will lead to the success of the country to be adopted with the global counterparts.

Nowadays, the placement of artificial prostheses in human skeleton, etc. is common due to different reasons such as fractures or deficiencies. Prostheses are structures that assist the performance of organs by reconstruction of some body parts through different methods to enable the organ to re-obtain its performance completely or partially and, since the use of external prostheses might lead to issues such as severe traumas, slow recovery and imposition of enormous hospital costs on the patient, therefore, use of internal prostheses can be an effective method for accelerating the process of improvement for the patient. By using CT-scan photos of a 54-year-old man weighing 60 kg and with a femur length of 36 centimeters, and also using a titanium prosthesis with diameters equaling 9 and 13 mm along with screws with diameters of 4 mm whose placement are with angles of ±4, ±4 and ±36 degrees, the geometry of the model has been provided and the model has been analyzed through the finite element method. Results indicated that in case of using the prosthesis with the diameter of 13 mm and screws of 4 mm with angle of +36, the least stress will be imposed on the bone and prosthesis.