2.
4.
The supports are unloaded after the settlement is stable for 48 hours.
According to incomplete statistics of relevant data, of the 83 kinds of collapse accidents occurred in China from 1992 to the first half of 1995, there were 16 floor (support) collapses, accounting for 19.3%; In 1992, in a major accident that killed more than 3 people nationwide, 59 people died and 20 were seriously injured due to floor collapse, accounting for 38% and 59% of the total respectively; Formwork support collapse has always accounted for a high proportion of major engineering construction accidents.
There are 35 points in total.
The beret pieces are connected with pins, and the beret beams are connected with flower windows to strengthen their own torsion resistance.
The cast-in-place bailey support is composed of steel tube column, sand box, distribution beam, bailey beam, bottom formwork, side formwork and support from bottom to top.
B.
Steel pipe column a, steel pipe column generally adopts diameter Φ 1000mm spiral steel pipe plays the role of transmitting the dead weight of beam structure, support load and construction load to the foundation.
6.
Each time the first level of load is unloaded, all measuring points shall be measured and recorded in detail, and the deflection during data analysis shall be compared with that during loading.
The loading process is divided into four stages: 0 – 30% – 60% – 100% – 130%.
The bailey beams are connected with flower windows to strengthen their own torsion resistance.
Formwork support is a frequent field of major casualty accidents.
Support erection 4.
3.
The xx high-speed railway basically adopts the bowl-buckle bracket.
In order to facilitate the removal of bottom formwork, side formwork and bailey beam, a sand box with adjustable height of 0.5m is installed between the top of steel column and I-beam.
When various construction supports collapse during bearing and use, most of them will cause quite serious consequences.
The bearing capacity of the replacement part is at least 250KPa, and special attention should be paid to the replacement of the mud pit and the bearing platform foundation pit when treating the foundation; The top surface is poured with 0.2m C25 concrete.
Along the line, from left to right, they are points 1 to 7.
5.
3.
The sections are I, II, III, IV and V from small mileage to large mileage; Each section has seven points, which are the corresponding lower distribution beam positions at the bottom of the flange, the top of the web, the two sides of the bottom of the bottom plate and the middle of the bottom plate.
What is their basic structure? What kind of safety accidents will happen due to engineering mistakes? Let’s study with you today! 1： The erection structure of steel tube column bailey beam 1.
The distribution beam plays the role of distributing the structural load, support load and construction load to the steel pipe column.
The cast-in-place simply-supported box girder with bracket and steel tube column bailey beam is widely used in bridge engineering.
(1) The collapse of formwork support has always accounted for a high proportion in major engineering construction accidents.
The upper cup buckle, adjustable base and adjustable supporting nut shall be made of malleable cast iron or cast steel, and the lower cup buckle, cross bar joint and diagonal bar joint shall be made of carbon cast steel.
The preloading load factor is 1.3 times of the beam span load.
Support foundation treatment (according to the calculated bearing capacity): the foundation is excavated to the original soil, the bearing capacity of the foundation is at least 180KPa, and the replacement of the foundation is not less than 0.6m with the 37 ash soil, and the foundation is compacted with the air tamper.
The unloading of the support is still carried out in a hierarchical manner, and the unloading is carried out in the reverse order of loading.
Support preloading In order to ensure the quality of the concrete structure of the box girder, the steel pipe scaffold support must be preloaded after the installation of the bottom formwork to eliminate the inelastic deformation of the support, the supporting square timber and the formwork and the impact of the compression settlement of the foundation.
The specific point layout is shown in the following figure: III.
The top of the column supports the distribution beam, and the lower part is supported on the cushion cap or foundation.
First, unload 30% of the part for overload preloading, then the weight of the top plate, then the weight of the web, and finally the weight of the bottom plate.
(2) The typical formwork support collapse accident occurred in recent years September 5, 2005.
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The preloading time is determined by the ground settlement of the supports.
The bowl buckle node is composed of upper bowl buckle, lower bowl buckle, upright bar, cross bar joint and upper bowl buckle limit pin.
Weld 10mm thick 110 at the bottom of steel pipe column × 110cm steel plate is fixed with expansion bolts at four corners.
Therefore, no matter what aspect, we must attach great importance to the study of formwork support collapse accident, and take strong technical support and management measures to prevent and eliminate the occurrence of formwork support collapse accident.
In order to ensure the stability of steel pipe columns, the adjacent steel pipe columns are connected with [10 channel steel.
Double Head Lifting Pin Anchor
The single beret piece is generally 3m long and 1.5m high.
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5.
At the same time, the actual value of the elastic deformation of the support and the foundation can be obtained as a reference for the setting of the pre-camber value data of the beam formwork.
2.
The preloading method is based on the concrete weight distribution of the box girder.
2、 The basic structure of the construction and erection of the full support is 1.
In particular, the collapse of the support in the pouring process often causes heavy casualties, huge economic losses and adverse social impact.
The preloading blocks or sandbags are stacked on the erected supports.
Support structure.
The cup buckle node of the vertical pole is set according to the modulus of 0.6m, and the sleeve and connecting pin hole are used for the extension of the vertical pole.
[20 channel steel is fixed on the pier body at the top and midspan of the steel pipe column.
In order to strengthen the stability of steel pipe column, “well” type support is set in the end of steel pipe column.
The specification of steel pipe for bowl buckle frame is Φ forty-eight × 3.5mm, the wall thickness of steel pipe shall not be less than 3.5-0.025mm.
There are five sections in the longitudinal direction of observation points and settlement observation: 2 meters at the end of the span, 1/4 span, 1/2 span, 3/4 span and 2 meters at the end of the span.
