Jose M. Adam

Full-Scale Testing of Axially Loaded RC Columns Strengthened by Steel Angles and Strips:

This paper presents the results obtained from full-scale tests on 14 reinforced concrete columns strengthened with steel angles and strips subjected to axial loads. All the columns were subjected to loading before strengthening. The influence of various factors on the behaviour of the strengthened column was studied. The results of laboratory tests show that the system of steel angles and strips is highly effective for increasing ultimate load in a column and also increases column stiffness and its ultimate strain. Furthermore, analysis of the results of the experiments allows the load transfer mechanisms which affect the behaviour of the strengthened element to be determined.

Falls from height during the floor slab formwork of buildings: current situation in Spain

PROBLEM One of the phases with the highest risk of falls from a height in the construction of a building is during the floor slab formwork stage. This paper analyzes this particular risk, as well as the most frequently used fall-protection systems. METHOD A survey was carried out to define the current situation in Spain with regard to falls from a height during floor slab formwork and the fall-protection systems used to prevent such a risk. RESULTS The results of the survey clarified the current situation in Spain with regard to this risk, and made it clear that there is considerable risk of falling from a height during the floor slab formwork stage. DISCUSSION All the safety systems analyzed presented a series of weak points that should be studied in detail before they can be used on building sites. IMPACT ON INDUSTRY The risk of falling associated with floor slab formwork and the most frequently used protection systems are analyzed. As no research had been carried out to date on this type of risk, we consider the research presented in this article to be a pioneer in the field.

Experimental and Numerical Results from the Seismic Study of a Masonry Bell Tower

This paper describes studies carried out to characterize the seismic behaviour of the San Nicolas bell tower in Valencia (Spain), built of masonry between the 17th and 18th centuries. A complete geometric description of the bell tower was carried out and a numerical model developed to obtain the seismic response and its relationship to the seismic Spanish Standard. The model was first calibrated by means of dynamic tests performed directly on the real structure. The calculations were carried out to fit a non-linear behaviour and a failure criterion which included smeared cracking was considered to model cracks on the tower. Five different synthetic accelerograms were introduced at the towers base level to represent the seismic forces. The numerical simulations showed satisfactory performance of the tower as to the basic seismic acceleration proposed by the Spanish Standard. The earthquakes were also scaled until high levels of damage were achieved.

Prediction of the shear strength of reinforced masonry walls using a large experimental database and artificial neural networks

Abstract This paper analyses the accuracy of a selection of expressions currently available to estimate the in-plane shear strength of reinforced masonry (RM) walls, including those presented in some international masonry codes. For this purpose, predictions of such expressions are compared with a set of experimental results reported in the literature. The experimental database includes specimens built with ceramic bricks and concrete blocks tested in partially and fully grouted conditions, which typically present a shear failure mode. Based on the experimental data collected and using artificial neural networks (ANN), this paper presents alternative expressions to the different existing methods to predict the in-plane shear strength of RM walls. The wall aspect ratio, the axial pre-compression level on the wall, the compressive strength of masonry, as well as the amount and spacing of vertical and horizontal reinforcement throughout the wall are taken into consideration as the input parameters for the proposed expressions. The results obtained show that ANN-based proposals give good predictions and in general fit the experimental results better than other calculation methods.

Limitations of Grundy and Kabaila’s Simplified Method and Its Repercussion on the Safety and Serviceability of Successively Shored Building Structures

AbstractOne of the most critical stages for a structure’s safety is its construction process, and this problem is even more acute in buildings with reinforced concrete structures. These structures ...The authors would like to express their gratitude to the Spanish Ministry of Education, Culture and Sport for funding received under the FPU Program (FPU13/02466) and to the Generalitat Valenciana (GV/2015/063).

Structural failures in cast-in-place reinforced concrete building structures under construction

Abstract Many published studies agree that the construction phase of a structure is one of the most critical as regards to its safety. During this phase, the loads borne by the slabs can be even higher than their design loads. When combined with the possible failure of the shores supporting the slabs, this situation can be critical during the construction phase of building structures. Cases of buildings that collapsed under construction include “2000 Commonwealth Avenue” (Boston, MA, USA) in 1971 and the “Skyline Plaza” (Fairfax County, VA, USA) in 1973, which have been widely reported. The OSHA (Occupational Safety & Health Administration, USA) also studied several cases. Two more recent cases occurred in 2017 in Kanpur-India and Mexico City, Mexico. In all these accidents one floor collapsed and the dynamic effect of the impact on the lower floors caused the progressive collapse of the entire building. The aim of the chapter is to provide a compilation of the best-known case studies in order to identify the causes and mistakes that were made. In addition, a compilation and analysis of recent collapses is provided to lay the foundations for engineers and researchers to work on mitigating and eliminating on-site construction failures.

Strengthening Layout Using FRP in Industrial Masonry Chimneys under Earthquake Load

Industrial masonry chimneys usually are considered as historical heritage since they remind the industrial revolution that took placed by the XIX century, shaping a particular landscape in many cities, what led many Town Halls to protect them as cultural heritage. In this work an assessment of the seismic vulnerability is performed to check the structural integrity according to a return period of 500 years. Detailed geometrical investigations took place and dynamic tests performed with the goal to obtain natural frequencies and structural damping using four seismic accelerometers at different heights and orientations. From the experimental results a numerical model has been calibrated adjusting numerical frequencies to match those experimentally obtained. Artificial accelerograms were generated specialized for the city of Valencia and the crack pattern was obtained corresponding to a return period of 500 years. After these analyses the model of the chimney was strengthened using strips of FRP and the calculations repeated to obtain the reinforced achieved regarding seismic vulnerability. Conclusions related to these calculations are outlined.