El objetivo de la presente invención es aumentar la rigidez de los encofrados integrados durante su disposición, facilitar el trabajo de los ingenieros civiles que pueden determinar con facilidad la construcción de las armaduras horizontales, al tiempo que se reducen los costes de fabricación de los mismos. Este objetivo se consigue mediante un encofrado que comprende dos paredes de encofrado (1,1´) paralelas colocadas una frente de la otra, provistas de barras perfiladas que forman unos tensores (2,2´) verticales, y que están conectadas por al menos un dispositivo de unión articulado que permite o bien mantener las paredes de encofrado (1,1´) con una distancia de separaciónque define un espacio destinado a recibir un material de relleno como el hormigón, o bien plegadas para su almacenamiento y transporte. El dispositivo de unión se caracteriza por el hecho de que comprende una primera barra horizontal (3) rectilÃnea paralela a la primera pared de encofrado (1) y que atraviesa los tensores (2) de dicha primera pared (1), una segunda barra horizontal (3´) rectilÃnea paralela a la segunda pared de encofrado (1´) y que atraviesa los tensores (2´) de dicha segunda pared (1´) dicha segunda barra (3´) estando situada enfrente de la primera barra (3), y una pluralidad de barras de unión (4) que conectan perpendicularmente las dos barras horizontales (3,3´), dichas barras de unión (4) estando articuladas alrededor de dichas barras horizontales (3,3´).</P>The aim of the present invention is to increase the rigidity of the integrated formwork during its arrangement, to facilitate the work of civil engineers who can easily determine the construction of horizontal reinforcements, while reducing the manufacturing costs thereof. This objective is achieved by means of a formwork comprising two parallel formwork walls (1,1´) placed opposite each other, provided with profiled bars that form vertical tensioners (2,2´), and which are connected by at least one articulated joint device that allows either to maintain the formwork walls (1,1´) with a separation distance that defines a space destined to receive a filling material such as concrete, or folded for storage and transport. The joining device is characterized by the fact that it comprises a first horizontal bar (3) rectilinear parallel to the first formwork wall (1) and that crosses the tensioners (2) of said first wall (1), a second horizontal bar (3´) rectilinear parallel to the second formwork wall (1´) and through the tensioners (2´) of said second wall (1´) said second bar (3´) being located in front of the first bar (3) , and a plurality of connecting bars (4) that connect perpendicularly the two horizontal bars (3,3´), said joining bars (4) being articulated around said horizontal bars (3,3´). </P>