How to design the stairs of residential buildings?

1. Beam-supported precast beam-supported reinforced concrete stairs refer to the stair structure mode in which the steps are supported by platform beams. Because the platform beam is arranged at the intersection of the stair platform and the inclined stairs, it avoids the unreasonable stress at the corner of the component and the difficulty in node treatment, and is widely used in a large number of civil buildings. Prefabricated components can be divided into three parts: step section (step section of slab or beam slab), platform beam and platform plate. 1, step (1) beam slab step beam slab step consists of trapezoidal inclined beam and step plate. Generally, a ladder inclined beam is arranged at both ends of the pedal, and the pedal is supported on the ladder inclined beam. (2) Plate Ladder A plate ladder is a whole or several slats with steps, and its upper and lower ends are directly supported on the platform beam. Because there is no stepped inclined beam, the bottom of stepped section is flat and the structure thickness is small, and its effective section thickness can be estimated according to L/20-L/30. Because of the small step slab and no ladder inclined beam, the position of platform beam is raised accordingly, which increases the clearance height under the platform. In order to reduce the dead weight of the step plate, it can also be made into a hollow member, and there are two ways to take holes horizontally and vertically. Horizontal drilling is more reasonable, easier and more commonly used than vertical drilling. 2. Platform beam In order to support the inclined ladder beam or ladder board, balance the horizontal component of the ladder and reduce the structural space occupied by the platform beam, the platform beam is generally made into an L-shaped section. Its structural height is estimated according to L/ 12 (L is the span of platform beam).