Lessons learned from the northridge earthquake

Rectangular tunnel boring machine (TBM) is applied for the tunnels’ excavation including a cross section of circular and rectangular shape within the various rocks and soil strata. Excessive structural forces, which is produced within tunnel linings, might affect the serviceability and safety of tunnels whose forces acting on tunnels linings during the initial design period have to be accurately calculated. Few numerical studies have been conducted on different soil-rectangular tunnel systems to clarify the critical response characteristics of cut-and-cover (rectangular) tunnels adjusted to transversal ground shaking. In this case, predicting the soil dynamic shear stresses developed around the tunnel is an elaborate task due to the interaction of TBM in the rectangular form and the rock. Despite doing the empirical studies in analyzing the rectangular tunnels systems, using artificial intelligence (AI) methods could significantly develop the optimization of TBM tunneling and decreasing the cost, error percentages, disturbance, and time-consuming complications related to tunneling. In this study, two algorithms, namely, support vector machine (SVM) and gene expression programming (GEP), were used to accurately predict the soil dynamic shear stresses developed around the tunnel. The models were developed and measured resulting that SVM can indicate a high-performance capacity in predicting the soil dynamic shear stresses developed around the tunnel through the rectangular TBM excavation machine.

Numerical assessment of rectangular tunnels configurations using support vector machine (SVM) and gene expression programming (GEP)

Unpredicted loading caused by blast or impact may lead to severe damage in structures. Such damage may affect the whole structural performance. Connections are the key contributor to the integrity and energy dissipation capacity of the structural steel systems and play the most important role in mitigating such consequences. In the view of the importance of connections, finite element analysis is used in this paper to study the behavior of braced steel frame under blast loading using ABAQUS finite element software. This Frame is adopted from a hospital building. Firstly, the behavior of the frame is investigated under near-field blast load to locate the regions that are susceptible to damage. Then according to the damage, five different possible reinforcing scenarios are proposed, and the advantages and drawbacks of each one are investigated. It is observed that asymmetrical deformations and damages are notable due to the front members’ severe local damage. The damage in the structure decreases rapidly as the height increases. In addition, the vertical web stiffeners and triangular plates on the top and bottom flanges eliminate the severe plastic strain and stress concentration in the connection zone causing the critical regions to move toward the middle of the beam that is desirable. It is also observed that continuous reinforcement of the beam webs with web sheets on both sides, significantly reduces the stresses on the web. This is a more effective way than the web stiffeners because of fewer stress changes in other members due to minor changes in the stiffness of the connected members. D D

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Investigation of different methods in strengthening braced steel frame under blast load

An artificial intelligence approach study for assessing hydrogen energy materials for energy saving in building

Evaluation of waste management and energy saving for sustainable green building through analytic hierarchy process and artificial neural network model.

ARTICLE INFO Article history: Received: January 2017. Revised: May 2017 Accepted: June 2017.

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F. Ghalamzan Esfahani

Papers

Finite element analysis of a rigid beam to column connection reinforced with channels