PhD Candidate, Structural Engineering
Alaa Al-Sammari is a PhD candidate in the Civil Engineering Department (Structural Engineering) at the University of Massachusetts Amherst. Alaa conducted his undergraduate study as a civil engineer at the University of Tikrit, Iraq and graduated from the Structural Engineering program of that university with MS Degree concentrating on finite element analysis of reinforced concrete slabs and shell systems. After graduation with the MS Degree, he worked as a lecturer, material testing consultant, and structural engineer. His solid background advanced him toward designing and supervising the construction of several residential and industrial buildings. With an experience of both general civil and structural engineering, he is continuing his study for the PhD degree in the Structural Engineering program at the university of Massachusetts Amherst. His research focuses on finite element simulations of bonded and mechanically anchored interfaces where different components are joined together to form new structural elements with better performance compared to conventional structures. His research work has focused on methods to model connections used to transfer interfacial shear between fiber reinforced polymer sheets or wood components and concrete.
Finite element simulation of bonded and mechanically anchored shear interfaces of externally applied FRP sheets to concrete and wood-concrete composites
Chair: S. F Breña (CEE Dept.)
Members: P.L. Clouston (ECo Dept.), A. J. Lesser (PSE Dept.), and S. Gerasimidis (CEE Dept.)
The need to develop new structural systems where two or more materials are combined to improve mechanical performance and reduce construction costs is the main motivation of this project. This research topic provides information on finite element methods used to simulate the behavior of bonded and mechanically anchored interfaces of externally applied fiber reinforced polymer sheets attached to concrete and wood-concrete composites. Three-dimensional finite element models were constructed to simulate the behavior of bonded structural systems. Two types of systems were simulated. The first type is fiber reinforced polymer- concrete joint system that consist of concrete, fiber reinforced polymer sheets and bonding materials. This system is used to rehabilitate concrete structures suffering deterioration where concrete is retrofitted by externally bonding a sheet or more of fiber reinforced polymer materials. The second type is a wood-concrete composite system used in floors, roofs, and bridge decks. This system employs shear connectors to transfer shear stresses between the wood and the concrete leading to full or partial composite action for strength and stiffness benefits. The system consists of a perforated steel plate of which half is epoxied into a route in the wood member while the other half is embedded in a concrete slab. Parametric studies were conducted based on the constructed models to investigate the behavior of each joint due to change in key parameters.
The objective of this work is to study the behavior of multi-component systems and the factors affecting slippage between the different components of these systems where lower slip induces higher level of composite action and consequently, improved overall structural performance of the composite system in terms of stiffness and strength.
Al-Sammari, A. T., Clouston, P. L., & Breña, S. F. (2018). Finite-Element Analysis and Parametric Study of Perforated Steel Plate Shear Connectors for Wood–Concrete Composites. Journal of Structural Engineering, 144(10), 04018191.
Wood–concrete composites are structural deck systems that benefit from the use of wood as a lightweight, sustainable substructure and concrete as a wear-resistant, vibration-damping top element. These systems are gaining in popularity for large-scale construction applications such as floors, roofs, and bridge decks. The wood–concrete composites employ shear connectors to transfer shear stresses between the wood and the concrete leading to full or partial composite action for strength and stiffness benefits. This project presents results of finite element (FE) analyses and a parametric investigation for one type of connector: a perforated steel plate of which half is epoxied into a route in the wood member while the other half is embedded in a concrete slab. The FE model was first validated against experimental push-out tests performed on a commercial product and then employed to examine the effect of several parameters of the connection: thickness of plate; insulation gap between concrete and wood; depth of embedment in concrete; and depth of embedment in wood. The results showed that thickness predictably affects shear capacity as well as ductility and stiffness (slip moduli) of the connector. It was discovered that higher stresses predominantly developed within part of the depth of embedment in both the concrete and wood, indicating a possible lower limit on the required embedment of the steel connector into the wood and concrete components.
Incorporating wood elements in large-scale construction in this way has the environmental benefits of using renewable materials while also lowering embodied energy during manufacture and reducing the overall carbon footprint of the built environment due to carbon sequestration of wood. Other advantages of using wood include reduction in construction time and cost due to wood functioning as permanent formwork and reduced foundation costs because of the high strength-to-weight ratio of wood.