Abstract The increase in the world population has caused cities to grow vertically, increasing the amount of high-rise buildings, which is why there is a need to develop building materials with greater efficiency, that is, resistant and with less density to the conventional. The objective is to analyze the mechanical behavior of buildings with portico system when being designed with lightweight concrete mixtures made with thermally expanded clay from materials in the San José de Cúcuta metropolitan area, Colombia. Eight structural models were made using the finite element method with the Etabs® software, varying the building height and the concrete type that was used, in order to compare the properties and lightweight concrete characteristics contrasted with the conventional concrete. The modeled buildings were located on land with a capacity of 200 KPa and residential use. The San José de Cúcuta city is located on an area of high seismic threat according to the Colombian construction of resistant earthquake. It was determined that lightweight concrete manufactured with materials from the San José de Cúcuta metropolitan area, Colombia, is structural since it has a compressive strength at 28 days of 26 MPa on average and equilibrium density of 1646.16 Kg/m 3 complying with the requirements minimums required by the Colombian regulation of resistant earthquake construction for a concrete to be considered light and structural. It was found that when using lightweight structural concrete in the design of joists and slabs, there is a 10% decrease in dead loads that reach the foundations of the structure, which implies a reduction in the dimensions of the foundations.