Simplified Cracking Analysis of Piers of Integral Structures. Experimental and Theoretical Study

Abstract

The maintenance experience of concrete structures has clearly shown that joints and bearings are the main cause for maintenance costs and deterioration of existing structures. This experience has sparked the interest of administrations and concessionaires for the design of jointless structures. There are many large integral structures that have been built in the last decades with good serviceability behaviour. Some examples in Spain are the Kuursaal Auditorium in San Sebastián, with a jointless length of 180 × 92 m2, the Office of Harmonisation of the Interior Market (OHIM) in Alicante with a jointless slab of 170 × 16 m2 or the central slab of the T4S Barajas Airport Terminal in Madrid with jointless dimensions of 120 × 80 m2. Despite the identified need for them and their successful implementation, integral structures remain a minority in modern structures. One reason for this is that the analysis of integral structures is difficult, since it involves non-linear analysis of very large structures. This is costly, requires the intervention of experienced engineers and is not and not always fairly rewarded. Also, as this type of structure is unusual, its acceptance by checking engineers can be problematic. On the other hand, the main structural codes allow to disregard imposed strains in analysis just by providing joints every 40 m or so. This paper looks at one serviceability aspect of integral structures which is the cracking of supports. It proposes and justifies, both theoretically and experimentally, a simplified method which can easily be applied by practitioners to evaluate the serviceability behaviour of the supports of long jointless structures. The method is based on isolating the column from the structure and providing results of the nonlinear analysis in graphical form.