Discuss the technical measures of formwork
Source: | Author:lichengcn | Publish time: 2017-08-09 | 5 Views | Share:
      1. application of pull bolts
      On the construction site, concrete columns, wall of the mould adopts the bolt support can be reduced, the bolt in a line, make the force directly, nut and tighten evenly spread to outside on the connecting rod, so that it will force cannot make force to the single block within the template or on the connecting rod;Otherwise, the local force will be localized and the template will be partially deformed, and the diameter and length of the steel bar should be adjusted to the design force requirement.Because many of the template accidents are caused by the breaking of the screw, the nut, or the crack in the hole.At the same time, it is also important to check whether the arrangement of pull bolts is reasonable.
      Actually, the site support is supported and used with the pull bolt.Shuttering of bolt along the long direction of the templates in a crack in the template every 600 mm or 750 mm placed a, long side direction perpendicular to the template is every a seam, namely every 600 mm set another row of bolt.This spacing is too large, and only the pull bolt can not withstand the lateral pressure of concrete and must be set up to be used together.
      The position of the bolt should be in the same template seam, up and down can not stagger a hole.Brace layout should be regular, side template if using within the bolt and base on pile head steel bar connection, should make the direction and the Angle of the brace has certain law, in order to calculate stress distribution.Check whether the transmission is direct and reliable.
      2. Theoretical analysis and reasonable construction
      The function of inner connecting rod is to connect the template to the whole and control the deflection of the template.The external connecting rod is perpendicular to the inner connecting rod, and the load is borne by the connecting rod.Support or pull the brace should focus on the external connecting rod, making the outer connecting rod to form the connecting beam of the equilibrium force.
      As pillar or wall at the bottom of the concrete level in the lateral pressure is bigger, the place of the bar should be than some top secret, and should form a band, or rail welding into hoop, support, the clip will also increase.
      The upper part of the template is best supported, so that it can withstand tension and pressure.If you only use the basket bolt or pull wire, you can only bear the tension, can't handle the pressure, and once the tension or pressure is touched, the template can be destabilized, twisted or deformed.
      The center of the column between the front and back of the center shall be connected by a tie rod, which will be good for the vertical and the whole of the column.
      The Angle of the column template can be matched with the yangjiao formwork to improve the stereo rigidity.It is good to prevent cross sectional deformation.
      The horizontal lift of the column wall is not only overcome by the pull clip, but also supported by the support.Column wall support resistance by different angles of horizontal force is also different, generally with 45 ° advisable, don't be too steep.Too steep to resist horizontal force, the template is easy to deform, the support point also easy to slide upward.
      To prevent the shifting of the point of force.For the lateral side template of concrete foundation, the outer diagonal support should be concentrated on the outer connecting rod. When the outer connecting rod is longitudinal, the horizontal bar deflection should be prevented.If the inclined support is on the soil slope, measures should be taken to prevent the subsidence of the ground and the support of the suspension will not work.
      When there are several concrete columns or walls, the shears are used to support each other in addition to the positioning of the connecting rod in the top, so as to prevent the whole geometry from destabilizing.
      3. quality assurance measures
      The edge of the concrete wall must be neat and straight.The connecting rod of the upper cornice template has a high rigidity and reliable stability.If it is a circular arc member, it is best to configure the circular arc truss, and the truss should be strong, reliable and not deformed.The connecting rod of the wall column must be made of double pipe.
      In order to control the section size, the wall thickness should be guaranteed to be consistent according to the thickness of the wall.It is not allowed to cast concrete without a straight line.The old template must be repaired and the new template size must be accurate.Too much error can change the size of the concrete section.The clip should be placed between the plates, so that the section size of the concrete will not increase with the clamping.
      Must check or use the theodolite to check the perpendicularity of two directions, control the center of the column, and correct the deviation in time.The column of the frame structure must also be controlled by the theodolite to ensure the overall vertical degree of the structure.
      In order to ensure smooth and smooth surface of the concrete surface, the surface of the template must be cleaned, scraped off the concrete residue, repaired holes in the hole, corrected dimensions and brush oil.Don't use unrepaired templates and imprecise templates.The surface must be smooth after the concrete vibrates.
      At the junction of the beam board, there is no Yin Angle mode on the construction site, multi-purpose metal pressure welding, not neat, not tight, a vibrating of the pulping.The sheet metal shall be welded in a uniform shade or pre - pressed sheet metal.The template should be spelt out to the outside of the beam mold to avoid the embedded beam mould to be removed.
      4. strictly control the position of the pre-position
      The deviation of the center line position of the pre-plate steel plate in concrete shall be no more than 10mm, and the deviation of the center line of embedded screw shall be no more than 5mm.The preburied steel plate and screw for horizontal position are fixed with fixed frame.In order to ensure the screw axis position, the fixed frame is required to form a frame with the Angle iron, and the steel plate or Angle steel of the hole is used to weld on the rack and fix the screws.The elevation of embedded parts is strictly controlled by means of measurement.For the column and the wall side of the embedded steel plate with 4mm small screws fixed on the template, cannot be welded, otherwise unmold difficult.
      5. Check and care of the template
      Before the construction of concrete, the quality of the template shall be reviewed by the supervision, technicians and quality inspectors.No problem before pouring concrete.When pouring concrete, avoid scratching the supporting part of the template, and set up special woodworking care. If the template is found, the concrete will be stopped immediately.Site calibration.Report to the project manager and technical staff immediately if the circumstances are serious.Study reasonable solutions
      6. the concrete is vibrates according to the rules
      The model is caused by the lack of reasonable support, improper support, excessive thickness of concrete casting, excessive lateral pressure, or too little supporting deformation or too long buckles.Concrete must be layered and vibrated, and the thickness of each layer of concrete shall be controlled within the allowable limits of the construction codes, and the concrete shall be finished before the concrete is started.There must be the construction of ramming scheme to overcome the phenomenon of indensification, honeycomb, hemp, and so on.
      7. Develop a plan to dismantle the mold
      Before the template is removed, it is necessary to develop a plan for the removal of the mould.The disassembly shall be constructed according to the measures to avoid safety accidents.
      8. conclusion
      Through the above measures, in several concrete construction has achieved good results, proved this method was done, to ensure the quality of construction of cast-in-situ concrete have played a role.