ISSN / EISSN : 0965-0911 / 1751-7702
Published by: Thomas Telford Ltd. (10.1680)
Total articles ≅ 525
Latest articles in this journal
Structures Buildings, Volume 173, pp 63-75; https://doi.org/10.1680/jstbu.17.00106
A hybrid composite precast concrete column (called the Smart column) was developed to increase the productivity of the tilt-up construction method. The Smart column, consisting of three precast concrete members connected by steel joints, is three storeys high. The joints where concrete is not poured during production consist of connection steels and rebars installed through the three precast concrete members, and these are possible failure areas due to stress concentration. Although the Smart column is designed safely through sufficient structural details, failure can occur during the tilt-up process, which clearly adversely affects projects costs and time scales. The results of a field experiment to analyse the safe erection of Smart columns are presented in this paper. The strains in the embedded rebars were measured during the tilt-up process in five different lifting procedures. All five lifting procedures exhibited small strain behaviour in the reinforcing bars, indicating no significant bending during the lifting procedures and thus proving the safe erection of a Smart column.
Structures Buildings, Volume 172, pp 859-870; https://doi.org/10.1680/jstbu.18.00010
Finite-element analysis (FEA) and an analytical model were used to estimate the ultimate flexural strength of reinforced concrete (RC) beams with corroded compression bars. Both models accounted for the deteriorated material's properties and geometry. The two models were verified against available experimental data and both showed good agreement. The analytical model was employed to study the effects of corrosion length, corrosion level, concrete compressive strength and concrete cover on the ultimate flexural strength of RC beams. Over 670 cases were investigated to estimate the influence of these variables on the ultimate flexural strength of RC beams with corroded compression steel reinforcement. The results of this investigation suggest that corrosion of compression steel reinforcement leads to a maximum flexural strength reduction of 20%, of which roughly 15% is due to spalling of the concrete cover on the compression side of the cross-section.
Structures Buildings, Volume 172, pp 882-901; https://doi.org/10.1680/jstbu.18.00055
In recent years, work has been dedicated to studying the behaviour of T-stubs with two bolts per row, which are covered in EN 1993-1-8:2005. Joints with four bolts per row are used in some cases, but they are not covered in the standards. The mechanical behaviour of a T-stub with four bolts per row was therefore analysed in this study, focusing on analysis of the evolution of the bolt forces and the prying force. The developed models were validated by comparing their results with experimental data. The parameters studied were the distances to the edges, the distance between the bolts and the position of the contact zone under the T-stub flange. Different measuring techniques were used to follow the displacement of the flange and the axial deformation of the bolts.
Structures Buildings, Volume 172, pp 922-934; https://doi.org/10.1680/jstbu.18.00131
This paper presents an experimental investigation to assess the influence of soil–structure interaction (SSI) on an unreinforced masonry structure under train-induced vibrations. For this purpose, a structure near a railway line was instrumented and monitored when subjected to five railway traffic vibrations. The measured vibrations were used to estimate the modal properties using a frequency domain decomposition technique. The variation in estimated modal properties against varying excitations indicated that the dynamic response depends on the source of excitation. Two finite-element (FE) models were also developed and updated through manual tuning, one with a fixed base and the other with a flexible base accounting for SSI. The modal properties and response time histories measured through experimentation were compared to those predicted by detailed three-dimensional FE models. A comparison between the base input force, base moment and peak displacement of both FE models was also performed. The results indicated that the effect of SSI on the fundamental mode shape and in the prediction of accurate response time histories of the investigated structure was significant. However, the effect on modal frequencies, base input force, base moment and peak displacement of the investigated structure under train-induced vibrations was observed to be very low.
Structures Buildings, Volume 172, pp 857-858; https://doi.org/10.1680/jstbu.2019.172.12.857
Structures Buildings, Volume 172, pp 871-881; https://doi.org/10.1680/jstbu.18.00016
In this paper, a seismic evaluation procedure based on an energy balance concept is presented for the cable-stayed bridge. In this method, the capacity curve obtained from the modal pushover analysis of the cable-stayed bridge is converted to modal energy capacity diagram. Then, by intersecting this diagram and the energy demand diagram for a selected ground motion, the dynamic target point is obtained. This method is employed on the cable-stayed bridge under Imperial Valley earthquakes with different peak ground motion, and the seismic demands are compared with the results from modal pushover and nonlinear response history analyses. It is observed that this energy balance method can estimate the seismic responses under the selected ground motions with proper accuracy. It should be noted, the OpenSees software is employed for modeling and analyzing of the cable-stayed bridge.
Structures Buildings, Volume 172, pp 805-818; https://doi.org/10.1680/jstbu.18.00057
Cold-formed hollow sections have a lower resistance capacity than hot-rolled profiles due to their welded seams. However, using design codes for such sections usually leads to an uneconomical and conservative structural design for compressive members. A series of numerical analyses was carried out to understand and evaluate the performance of standard and concrete-filled cold-formed columns. A numerical model was developed and calibrated against experiments, considering residual stresses, initial geometric imperfections and material properties. The developed numerical model was able to represent the experimental results accurately in terms of failure mode, deformed shape and compressive resistance. Based on the results, an alternative buckling curve is proposed for plain steel and steel–concrete composite columns. This design curve was determined from the results of a parametric study and led to the use of new values of the imperfection factor and initial non-dimensional slenderness for the Eurocode design procedure. A reliability index was also evaluated to estimate the scope and validity of the proposed curve.
Structures Buildings, Volume 172, pp 819-835; https://doi.org/10.1680/jstbu.17.00138
Substantial damage to buildings from seismic pounding is a result of earthquakes in many urban areas. This study investigated the effects of pounding in low-rise buildings, which have been individually designed for seismic resistance, using a three-dimensional numerical model. The poundings between the heavier and lighter buildings were conducted in 4 cases under the floor to floor collision and zero separation gap, and the total heights of the buildings were varied. The ratio of the story mass between the heavier to the lighter buildings in all cases is 1.7. The results demonstrated that the heavier buildings were almost unaffected from the collision, and that seismic design without pounding consideration is acceptable. Nevertheless, the pounding had more influence on the lighter buildings. A significant increase of the inter-story drift and the story shear force can be found. At the top floor of the lighter building, the inter-story drift and the story shear force are increased in the range of 35-73% and 20-46%, respectively, compared with the no pounding events. In addition, severe damages at beam-column joints are found. Hence, the lighter buildings need special attention under a seismic pounding event.
Structures Buildings, Volume 172, pp 781-788; https://doi.org/10.1680/jstbu.18.00080
The results of an experimental study on the effect of the partial replacement of ordinary Portland cement with nanosilica (NS) on the mechanical and durability properties of concrete are presented. Concrete mixes were made with varying NS contents at a constant water/binder ratio of 0·40. The test results demonstrated that the inclusion of 3% NS as a partial replacement of cement enhanced the mechanical properties and reduced the water penetration depth and water absorption of the concrete, resulting in overall improved performance. Compared with normal concrete, the water penetration depth and water absorption of the NS concrete was reduced by 42·85% and 36·84%, respectively. The carbonation depth was also reduced as a result of cement replacement with NS, leading to enhanced concrete durability. These enhancements in the mechanical and durability properties were mainly due to the high fineness and increased pozzolanic activity of the added NS.
Structures Buildings, Volume 172, pp 768-777; https://doi.org/10.1680/jstbu.17.00206
The present work complements recent attempts to investigate the causes of vulnerabilities inherent in half-joint structures. Herein, such vulnerabilities are attributed to shortcomings of the mechanism of force transfer underlying the adopted methods of design, rather than the detailing of the specified reinforcement as widely believed. The work is intended to demonstrate that the forces in half-joint beams are transferred by beam action, and not by the strut-and-tie mechanisms assumed to develop in the presence of the specified reinforcement. Through the use of the compressive force-path method, which has been developed on the basis of a beam mechanism of load transfer, it is shown that the predictions of half-joint beam behaviour correlates closely with the findings of a finite-element analysis package which was at first shown to be capable of successfully reproducing the experimentally-established structural behaviour of such beams.