Masonry bridges and arches

Part of the wall that blocks the window or doorway, called a jumper. If the load is transferred from the floor to the wall directly above the opening, apply a load-bearing precast concrete bridge. In the absence of such a load to block openings width of less than 2 m used concrete or non-bearing ordinary brick bridges in the form of masonry in solutions with high-strength reinforcing bars to keep the bottom row of bricks. Instead of the ordinary sometimes make canted jumpers that are at the same time, architectural details of the facade.
With the same purpose during the flight to W ,5-4 m often erect arched bridges. Masonry arch type is also used to shut-off devices in buildings, are called vaulted ceiling (vault). When clutch jumpers all longitudinal and transverse joints necessarily entirely filled with a solution, because this masonry works not only for compression but also bending. With a weak filling solution under the influence of vertical joints first load shifts individual bricks, and then the destruction of masonry.

Ordinary jumper
Ordinary jumper spread of selected whole bricks with horizontal rows and compliance rules ligation conventional masonry. Height ordinary jumper 4-b of masonry, and length - 50 cm greater than the width of the opening. Jumpers are used for masonry mortar shall be 25 marks. Under the bottom row of bricks in the dam in a layer of thick solution of 2-W cm placed at least three rebar diameter of round steel min b mm, usually at the rate of one rod cross-section 0.2 cm per half-brick thick wall, if the project is not requires a strong reinforcement. Reinforcement takes tensile forces occurring in masonry. The ends of the round rods pass beyond the limits of the opening is 25 cm and bent around the brick (Fig. 4b).

Кладка рядовых перемычек

Fig. 46. Ordinary masonry bridges: a - the facade, 1 - reinforcement stitches b - section B - laying the plank formwork d - laying on inventory kruzhalah, 1 - reinforcement stitches, 2 - board; W - wood whirling 4 - tubular whirling.

Ordinary jumper made using temporary formwork boards thickness of 40-50 mm. On it spread a solution, which then vtaplivayut rebar. The ends of the formwork opirajut on bricks, fired from masonry, after removing the formwork to be cut down.

Canted and the arched bridge

Canted and arched bridges spread of ordinary ceramic brick by forming the wedge-shaped seams of thickness at the bottom of the jumper at least 5 mm at the top to 25 mm. Masonry are transverse rows formwork retained wheels. Prior to the laying of the jumpers to build a wall to the level of the jumpers, laying out at the same time supporting part (heel) of podtesannogo bricks (pattern determine the direction of the reference plane, that is, the angle of deviation from the vertical). Then on formwork mark out rows of masonry in such a way that their number was odd, considering the thickness of the seam. Rows of masonry in this case is not considered vertically and horizontally.
Central odd number of bricks is called locking. It should be in the center of the jumper in the upright position. Canted and masonry arched bridges are evenly on either side of the heel to the castle so that it is in the lock jammed central odd brick. Correct direction of stitches check cord reinforced at the intersection of the lines supporting the mating parts (toe). When flying over 2m canted clutch jumpers are not allowed.

Arched bridges and arches
Arched bridges and arches and vaults spread in the same sequence as the canted jumper. The joints between the rows should be perpendicular to the curve of the line forming the bottom surface of the arch, and the outer surface of the masonry. Masonry joints give canted form with broadening the top and narrowing down. Such an arrangement of masonry and share their beds matches the first rule of cutting masonry, as in the arches and vaults of the force from the load changes its direction, acting on a tangent to the curve of the arch. Bed series are perpendicular to the direction of pressure (Fig. 47).

Кладка перемычек

Fig. 47. Masonry bridges: a - canted b - Bow 1 - direction of the reference plane, 2 - brick castle in - arch d - joints masonry: Z - line 4 - template-gon.

Masonry arch bridges are formwork corresponding form in the same order as canted clutch jumpers. The direction of the radial joints and proper installation of each series of test on the cord, fixed in the center of the arch. String and pattern-gon, one side of which has a shape corresponding to the curvature of the arch, and identify and verify the position of each row of masonry.
Formwork for construction of masonry vaults and arches should be such that it could provide an even lowering it when raspalublivanii. For this purpose under kruzhalami put wedges, with the gradual weakening of the formwork are omitted. Incubation periods and canted arched bridges on formwork according to the outside temperature in summer conditions and the brand of solution can be from 5 to 20 days, and ordinary jumper - from 5 to 24 days.
Share with your friends a link to this page, or add to