Improving Seismic Safety of RC Elements by Using Advantages of Rectangular Spiral Stirrups Cornel Doniga & Gabriela M. Atanasiu Technical University “Gheorghe Asachi” of Iasi, Romania SUMMARY: In the last decades, the prescriptions for RC structural seismic design have produced minor improvements in the steel reinforcement technology. In the fabrication and handling of reinforcement, an important amount (30 to 65 percent) of the resources is dedicated to transversal reinforcement stirrups. If the technology used in fabrication of steel cages for circular section concrete drilled piles would be applied to common rectangular section concrete elements, significant benefits shall be obtained. The principle of rectangular spiral stirrups implies a rectangular loop that is unfolded like accordion to obtain the steel transversal reinforcement. The benefits of using these new stirrups include: consumption of less material (savings ranging from 6 to 14 percent); the mitigation of element’s failur e due to stirrup opening; increased productivity; increased rigidity of the reinforcement cage prior to concrete pouring; time and energy savings in production. For validation purposes, comparative analyses have been carried out with ATENA 3D. Keywords: transversal reinforcement, spiral, improved behaviour, material savings, comparative analysis 1. INTRODUCTION During the latest earthquakes in Europe, and world wide, many classes of reinforced concrete RC elements have suffered while the structures were exposed to seismic/dynamic loading. Looking into the latest development of the seismic prescriptions, aiming to prevent severe damages of RC elements, it has been noticed that there is relatively little concern on the shape and optimal placement of steel reinforcement in these types of structural elements. Although significant achievements have been reached in structural design and building engineering, minor improvements can be identified for the steel cage reinforcement assembly in the last decades. When considering the RC linear elements (girders and columns), an important amount of resources are dedicated to fabrication and handling of the transversal reinforcement (stirrups). For a RC structural element, depending on the design data, geometry and location, the resulting cost of transversal reinforcement may reach a percentage of 65 from the cost of entire reinforcement cage of that structural element. In most cases, the longest operation in reinforcement cage fabrication is represented by production and assembling of the stirrups. Significant benefits shall be obtained if the principles used in the fabrication of steel reinforcement cages for circular section concrete drilled piles will be applied to common rectangular section concrete elements. This paper deals with the advantages of using spiral stirrups in RC elements of constructions exposed to earthquakes. The constructive principle of rectangular spiral stirrups implies a constant section rectangular loop that is unfolded like accordion when used to obtain the steel cage reinforcement. Several important structures collapsed due to stirrups opening when subjected to important seismic actions. This risk is minimized in the case of using spiral stirrups, since it consists of only one wire as transversal reinforcement, throughout the entire length of the element.