No abstract

a laboratory of experimental and numerical Modelling of Materials and structures in civil engineering (laMoMs), university Mouloud Mammeri of Tizi ouzou, Tizi ouzou, algeria; b l2Mgc, cergy-Pontoise university, cergy-Pontoise, france; c laboratory of Materials and durability of constructions (lMdc), university Mentouri of constantine, constantine, algeria ABSTRACT Self-compacting concrete (SCC) is a new material able to be put in place without vibration. However, this advantage is offset by some drawbacks, such as plastic shrinkage, one of the causes of cracking in concrete. Furthermore, the presence of fines absorbs a large amount of water and therefore minimizes bleeding. This paper endeavours to provide a better understanding of the appearance of plastic shrinkage cracking, and to justify his relation with bleeding phenomena. Five SCC formulas with different W/C ratios were prepared and compared to the same range of ordinary concrete (OC) in terms of restrained shrinkage (cracking width). At the same time, a study of cracks' propagation over time (cracking length) was conducted on the equivalent mortars (mOCe, mSCCe). Mixtures were placed in different hot environmental conditions. The results showed that bleeding significantly reduces cracking length and has no effect on cracking width. In the second part, extra water and superplasticizer was proposed as a solution to prevent SCC cracking and findings show the addition of 10% of water reduces cracking length and a slightly lower addition of superplasticizer reduces SCC's crack width.

No abstract

Abstract. In the present paper, a finite element approach calculating the rising and the relative slip of steel base plate connections is proposed. Two types of connections are studied, the first consists on a base plate welded to the column end and attached to the reinforced concrete foundation by two anchor bolts. These bolts are placed on the major axis of the I shaped section used as column, one anchor bolt on each side of the web. In the second configuration, the connection includes a plate base and four anchor bolts placed out side the flanges of the I shaped section or hallow form. To take in account the real behaviour of this connection, a model by finite elements which considers count geometrical and material no linearties of the contact and cracking in the concrete foundation. To study the rising of the base plate, an approach treating problems of contact-friction between the base plate and the foundation is developed. This approach is based on a unilateral contact law in which a Coulomb friction is added. The numerical resolution is ensured by the increased Lagrangien method. For the behaviour of the concrete foundation, the developed model is based of a compressive elastoplastic model. The heights rising-rotations and the heights rising-slip displacements curves are plotted.

The present work concerns a numerical study of the behavior of reinforced masonry (RM) structures under seismic loading. These structures are made of small hollow elements with reinforcements embedded in the horizontal joints. They were dimensioned according to the rules and codes commonly used. They are subject to vertical loads due to their own weight, and to horizontal loads due to seismic forces introduced by the accelerograms. The software used is the non-linear analysis program Drain2D, based on the finite element method, where the shear panel element was introduced. A series of calculations was performed on a number of structures at different levels, excited by three major accelerograms (El Centro, Cherchell, and Kobe). Throughout the study, our main interest is to evaluate the behaviour factor, the ductility, and the failure mode of these structures while increasing the intensity of earthquakes introduced. The results of this present study indicate that the average values of the behaviour factor and the global ductility are of the order of q≈μ≈3.00. The reinforced masonry structures studied have been broken by interstage displacement. The results given by the study are comparable to those given in the literature and in Eurocode 8. The behavior of reinforced masonry under a seismic load is similar to the behavior of reinforced concrete; it is a ductile behavior that allows the dissipation of the energy transmitted by the earthquake. These numerical studies confirm and complete the experimental work carried out by other researchers. Doi: 10.28991/CEJ-2022-08-10-012 Full Text: PDF