Dynamic testing of simply suported decks with prestressed concrete beams on the Almorchón River bridge (Dam of la Serena)

Abstract

Dynamic tests on the Almorchón river bridge decks were carried out due to the existing interest on the dynamic behaviour of simply supported ""I"" beam decks with a small number of beams (3-4) and spans over 35-40 m. Vertical displacements and accelerations at varios points were registered under the action of a 40 t truck crossing the bridge at different speeds. Dynamic amplification factor and damping (through logarithmic decrement) were estimated from the displacement signals. Natural frequencies were studied by means of the Fast Fourier Transform (FFT) or acceleration signals. Experimental values are presented and compared with expected values derived from a simple theoretical analysis.