Three-dimensional (3D) printing is a procedure used to create 3D objects in which consecutive layers of a material are computer-controlled produced. Such objects can be constructed in any shape using digital model data. First, this paper presents a state-of-the-art review of the advances in 3D printing processes of construction. Then, the architectural, economical, environmental, and structural features of 3D printing are introduced. Examples of 3D printed structures are presented, and the construction challenges facing Jordan, that encouraged this study, are stated. Finally, a precise description regarding the impact of 3D printing is provided by comparing conventional construction data of Ras Alain Multipurpose Hall in Jordan and the expected data if the same building has been built using 3D printing. The suggested model is generated using Revit software. As a result of this study, an understanding of 3D printing procedure, mechanism of action, and its impact on the future of construction and architecture through economical, structural, and environmental parameters is achieved. This leads to encourage engineers and contractors to take this subject into account for construction in Jordan.

The standard design procedure for tube and fitting connections assumes that the connections are only subjected to non-cyclical loads. This paper presents the results of experimental tests and theoretical calculations of the moment-rotation capacities of three common connections -sleeve couplers, swivel couplers and right-angled couplers. The results show that under a cyclic side load, such as that occurring by wind loading, looseness affects the capacity of the connections. For all three types of coupler looseness is shown to be relatively high which will reduce the stiffness of the connection under side loads. For sleeve couplers the effects of axial load in the tubes also affects the coupler stiffness and the maximum bending capacity of the joint. This implies that the common European code BS EN 74-1 for the connection should be changed to consider the loss in stiffness and maximum side load capacity under axial loads and looseness which are ignored in the standard. The standard assumption for right-angled and swivel couplers is that the connection can be assumed to be rigid about an axis normal to the plane containing the two tubes being joined. This is shown to be incorrect as the connections are shown to have stiffnesses about this axis which is of a similar order to the stiffnesses about the other axes.

Numerous existing formulas predicted the ultimate interfacial bond strength in concrete-filled steel tubes (CFST) between steel tubes and concrete core without investigating the whole response under push-out load. In this research, four models are proposed to predict the interfacial behavior in CFST including the post-peak branch under the push-out loading test based on 157 circular specimens and 105 squared specimens from the literature. Two models (one for circular and one for squared CFST) are developed and calibrated using artificial neural network (ANN) and two models (one for circular and one for squared CFST) are developed based on multivariable regression analysis, analysis of variance (ANOVA). The shape of the specimen (circular or squared), diameter of the tube, thickness of the tube, concrete compressive strength, age at the time of testing, and length of the specimen are the main factors considered. These models are then compared to other existing formulas to verify their capability to better predict the ultimate interfacial bond strength. It is found that the ANN model gives better results for most of the considered data. It is also found that ANN models can predict the overall bond-slip response for the considered dataset. In order to simulate the response of any CFST column using finite element (FE) method, it is vital to have sufficient input data on the overall bond-slip behavior between the interior face of the steel tube and the exterior surface of the concrete core including the post-peak branch. Accordingly, the suggested ANN model is used to generate the required input data related to the cohesive behavior and damage along the interface in ABAQUS model to simulate the response of two circular and two squared CFST columns under concentric compressive load. The results are in good agreement with experimental outcomes. The cohesive criterion and damage interface that are used based on ANN models in FE are found to be sufficient and can be adopted to model CFST columns.

No abstract

The response of reinforced concrete (RC) shear wall as a lateral resisting member has been studied extensively, but it still demands a general practical model that identifies the envelope within which load-drift paths occur during cyclic loading. Such a broad model is vital to ensure adequate lateral strength to resist reversal loadings imposed on these walls during earthquake events and ductility to measure inelastic deformation capabilities. A new model to define the backbone curve is developed in this paper for squat, intermediate, and slender flanged and nonflanged RC walls. The most common failure modes observed in the field and laboratory experiments are investigated and incorporated in the proposed model to estimate the response of these walls from elastic range until ultimate failure. The main parameters controlling the estimation of drifts that features the backbone curve thresholds are presented in this paper. The results of proposed model are compared with the outcomes of 117 specimens experimentally tested by other researchers. Also, the results are compared with Federal Emergency Management Agency (FEMA) 356, the updated American Society of Civil Engineers (ASCE)/Structural Engineering Institute (SEI) 41, and Eurocode (EC8 and EC2) provisions which reveal that only one general model, proposed in this paper, can capture the response of RC structural walls with an aspect ratio ranging from 0.35 to 2.5 and an axial load ratio from 0 to 0.4 with good agreement with experimental outcomes. K E Y W O R D S cyclic loadings, flexural failure, nonlinear dynamic modeling, shear failure, sliding shear, web crushing