Concrete Beams Provide Greater Resistance to Impact

The Structural Engineering Group from the School of Civil Engineering at the Technical University of Madrid (UPM) has completed a project on analyzing the impact resistance in concrete, allowing them to follow up with a study on the behavior of protection structures when exposed to rock fall.

Headed by Professor Carlos Zanuy Sánchez, the Structural Engineering Group carried out impact tests on beams using a free fall machine in the sStructures lLaboratory. Developed by Servosis, the machine features piezoelectric force transducers with CFW load washers by HBM (CFW-190 and CFW-700), which are able to detect forces with the maximum precision possible. Reinforced concrete beams have a tendency to fail under shear load due to minimum energy absorption capacity during impact. Tests were therefore conducted to identify the improvement potential for resistance using beams with metal fiber reinforcement.

Tests Using a Free Fall Machine

The tests were performed on seven different types of concrete and three types of fiber: 0 percent (without fiber), 0.5 percent and 1 percent. Measuring 2,000 mm long and having a rectangular format (125 mm wide and 250 mm high), the beams were subjected to impact from a steel mass weighing 200 kg (with a radius of 29 mm at the point of contact), which was dropped from a height of 1.75 m at a speed of 5.9 m/s. The findings from the tests on the Servosis machine that was fitted with HBM testing and measuring equipment revealed that it is possible to prevent shear failure and improve safety depending on the type of fiber. The HBM transducers guaranteed the required precision when it came to recording impact and reaction forces, providing an accuracy of 4.3 pC/N. Piezoelectric accelerometers (PCB 353B14) with an accuracy of 5 mV/g2 were used to check vertical acceleration and the weight of the steel ball.

Customized Support

Servosis and the Structural Engineering Group opted for HBM due to the trust they have in HBM products and the support that its specialists provide when it comes to developing a solution which meets specific project requirements. As Joaquín Gonzalo, CEO and Technical Director at Servosis, stated during the construction process for the free fall machine:

“HBM has gained our trust thanks to its testing and measuring products and its cooperation in selecting the right products to achieve the best possible results.”

The Customer

The Structural Engineering Group at the UPM

The Structural Engineering Group at the UPM forms part of the Department of Continuum Mechanics and Structures at the School of Civil Engineering at the Technical University of Madrid (UPM). Besides teaching basic and advanced subjects in the structural engineering program at the School of Civil Engineering, the group also conducts research projects in the field of structural engineering. It also focuses on promoting structural engineering as a fundamental branch of civil engineering and provides a specialized service to both the public and private sector.

Servosis

Founded in 1988, Servosis is a Spanish company which designs, develops and manufactures testing machines and electronic and mechanical systems used for quality control and analysis of materials, servo systems, machine and industrial process control, robots, measurement systems, and data acquisition.

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