I. Overview of the Project
Modern Nanyang Mansion has 23 floors above ground, with a total height of 98.80m and a single floor area of 2,300m2. It is a full cast-in-place frame shear wall structure. The standard height is 4.0m, including two kinds of columns (diameter 1500mm) and special-shaped columns (trapezoidal cross-section), with 8 columns on each floor. The core tube is square, and the wall thickness is 500mm, 450mm and 300mm. Beams are mainly divided into five types, of which KL- 1, KL-2 section is 1 100×900mm, and KL- 1 elevation is a folded arch beam. D-B is an inclined beam with a cross section of 1 100× 900 mm, S-B is 1 100×900mm, and the secondary beam KL-4 is 450× 800 mm ... The floor thickness is1.
In order to speed up the construction progress and ensure the requirements of the total construction period, according to the actual situation on site, it is decided to adopt the shaped steel formwork for the column and core tube shear wall. At the same time, considering the convenient and quick assembly of column formwork, and the construction of this project is divided into four water sections, it is decided that the column is equipped with 3 sets of formwork and 4 sets of special-shaped column formwork, which are used in four water sections. However, the installation of the core wall formwork is slow, so a full set of formwork is provided to ensure the construction period.
Beam slab formwork is supported by conventional methods, and panels are all made of bamboo veneer. Bowl-buckle scaffold is used for support.
See attached figure 1 for the division of construction flow section.
Second, the column template and its supporting system
1, cylindrical template
There are 8 pillars on each floor, which are distributed around the building. L 1-L2 layer has a diameter of 1800 mm, and formwork is proposed to be used for the on-site substructure construction. The diameter from L3 floor to the top is 1500mm, and the height of standard floor is 4 m, so it is planned to adopt shaped steel formwork for construction.
Column formwork is configured according to the standard floor. The cylindrical formwork is composed of two halves, with a diameter of 1500mm and a height of 2.9m During construction, the two halves are hoisted in place by tower cranes, and the whole is composed of bolts. Column concrete is poured to 20-30mm below the elevation of beam bottom.
Before the formwork is installed in place, mortar leveling layer should be made according to the column lateral line played in advance to ensure the bottom is tight and prevent slurry leakage. After the column is installed and positioned, wipe the bottom of the column template with 1: 3 mortar and chamfer it to avoid slurry leakage. At the same time, four positioning supports are welded on the main reinforcement of the column to avoid the whole bottom of the column from moving or tilting.
Because it is a shaped steel formwork, there is no notch cleaning at the bottom. Clean the formwork before the formwork erection, and pour concrete immediately after the formwork is in place.
The specific construction process is as follows:
1, vertical and horizontal axes and peripheral lines pop up on the floor surface.
2, welding, binding column main reinforcement, stirrup
3. Weld the positioning support iron at the bottom of the main reinforcement to ensure the bottom position of the template when clamping.
correct
4、? The bottom is leveled with mortar outside the column line.
4, hoisting steel mould in place, installation
5. Wipe the bottom with 1:3 mortar.
6、? Supporting formwork fixing system
7、? Check the template position and verticality.
8、? deposit concrete
9、? Dismantle formwork
The schematic diagram of the cylindrical template is shown in Figure 3.
2, special-shaped column template
There are 8 special-shaped columns on each floor. The cross section of the column is trapezoidal. The first floor column is 5m high, the second floor column is 6m high, and the other floors are 4m high. It is proposed to adopt the shaped steel formwork for the construction.
See attached figure 4 for the layout and fixation of formwork:
The concrete construction technology is the same as that of cylindrical formwork.
Three, the core tube shear wall template
In order to speed up the construction progress, the core tube shear wall formwork is equipped with a full set of steel formwork.
The wall formwork is made of ordinary large steel formwork. According to the size of the wall, several large steel templates are assembled into large templates, and adjacent large steel templates are connected by bolts. Non-standard small formwork is connected by additional back ribs in addition to bolts.
Generally, the large steel formwork is the frame structure of No.8 channel steel, the longitudinal side ribs of No.8 channel steel, the transverse side ribs of 8mm thick steel plate, the internal transverse small ribs of L50x5 angle steel, the hot rolled steel panel of 6mm thick, and the horizontal back ribs of double [10 channel steel, which are welded with the formwork. 25 through holes are drilled on the formwork panel with a horizontal spacing of 600mm and a vertical spacing of 900.
The height of standard layer and external wall formwork is 3200mm, and the wall-penetrating pole adopts M20. The spacing between wall-penetrating rods is 900X900.
The construction method of the junction of wall and beam is: the formwork at the junction of wall and beam is kept open except for the eight-character beam, and the wooden box is embedded on site to solve the problem, and the rest of the walls, beams and plates are poured twice.
Corner formwork is determined according to the wall thickness and formwork splicing structure. In order to ensure the corner size, the construction technology of installing the internal corner template first and then installing the template is adopted. The standard layer internal angle templates are 3200 respectively.
* 197* 197 and 3200*300*300 (used for the corner of external wall), and L75*6 angle steel is used as the external formwork. Refer to attached figure 5
In this project, the construction technology of pouring concrete directly to form fair-faced concrete is proposed for the outer wall of the core tube, and plastering is not required, so the requirements for formwork flatness are higher. When shuttering on the wall for the second time, wrap 150mm at the lower part of the formwork, and stick a sponge on the poured lower wall. The sponge will be clamped by the wrapped formwork to avoid concrete slurry from polluting the lower wall.
Four, beam and plate template scheme
The beam bottom formwork and floor formwork are supported by conventional methods, the panel is made of multi-layer bamboo plywood, the top joist is made of 50× 100 m3, and the joist is made of 100× 100 m3. The support system is bowl-buckle scaffold. See the attached drawings for the floor plan of beam slab roof.
The side formwork of the beam adopts customized steel frame bamboo veneer.
Scaffolding adopts Ф 48× 3.5 round steel pipe, with horizontal connecting rod spacing of @ 1200, and a horizontal support is set 500 meters above the ground, with vertical rod spacing of1.2 *1.2m. ..
There are three main types of standard layer beams:
1. The cross section of the annular beam with trapezoidal column connected to the core tube is1100 ~1300 *1100, which is an arched broken-line beam.
2. The cross section of the surrounding annular coupling beam is 800* 1 100.
3. The radiation beam sections between the core tube and the surrounding ring beam are 450*800 and 450*500.
Due to the large cross-section and span of the beam and the heavy weight, the arrangement of the lower support system of the beam is determined as follows through calculation. Add a vertical heavy garden steel support at the lower part of the beam @ 1200. Along the beam direction, a horizontal tie rod is set at 500mm from the ground in the horizontal direction, and it is connected with the scaffold supported by the surrounding plate. There is also a horizontal brace on it every 1200mm. So as to prevent the riser from becoming unstable due to compression.
Schematic diagram of beam slab formwork support is as follows:
Because the beam height is above 1000mm, the lateral pressure of concrete is large, which is between the beam and the bottom die.
F 12 pull bolts are used to fasten the side formwork to prevent the formwork from bursting and bulging in the middle. Pull down the bolt and put a jacket on the plastic pipe.
Construction sequence of beam and slab: erection of beam and slab support frame? Laying beam slab bottom formwork? Binding beam reinforcement
Installation of beam side formwork and bottom formwork binding plate reinforcement acceptance pouring beam slab concrete.
In order to speed up the construction progress, three standard floors are prepared for the floor formwork and its supporting scaffolding.
Materials are recycled.
Five, the removal of the template
Due to the high grade of concrete used in this project, columns and walls are C 60(C50), beams are C40 and slabs are C25. Therefore, in the case of full maintenance, in order to speed up the construction progress, the formwork should be removed as soon as possible. The side formwork of column and shear wall can be removed only after concrete pouring 12 hours, and the floor can be removed only after the design strength reaches 75%. The beam span is large, and the formwork cannot be removed until it reaches the design strength of 100%. However, after the formwork at the bottom of the beam is removed, a row of heavy supports still needs to be reserved in the middle, and it can be removed only after the upper load is completely removed.
Six, quality assurance measures:
Note: The assembly area of the above indicators is calculated as 2 100*2000MM, and the indicators can be appropriately relaxed when the assembly area is large.
2. The fittings must be firmly inserted, and the bearing surfaces under the pillars and diagonal braces should be flat and padded with sufficient compression area.
3. When the span is greater than or equal to 4.0m, the formwork shall be arched, and the elevation difference of the arched beam slab shall be 3‰ of the beam span.
4. Wide adhesive tape must be used to stick between the seams of the floor formwork to avoid slurry leakage.
5, embedded parts and reserved holes must be installed accurately and firmly.
6. The walls and columns shall be leveled with cement mortar, and the lower openings shall be leveled with positioning benchmarks prepared in advance. When the template is installed on the wall column, it should have reliable support points and correct its straightness.
7, plywood joints must have a wooden back edge, template flat-fell seam to ensure strict don't leak slurry, in the wall or beam joints must add plastic hose pressure seam, beware of leak slurry.
8. After the wall formwork is hoisted in place, level the lower facade and approach the positioning datum, adjust the verticality of the formwork on both sides and fix it with support.
9. Pillars supported on multiple floors should be on the same vertical centerline from top to bottom.
10, the transverse keel adopts the whole pole, and the joints are staggered.
1 1. In order to ensure the quality of the wall and reduce slurry leakage, a sponge strip is attached to the root of the formwork at the angle of yin and yang. During the external wall construction, in order to ensure the appearance quality of the lower wall, rubber strip and sponge strips should be pasted on the inner side of the wood square at the root of the upper formwork.
12, the template needs to be maintained. After the formwork is removed, it should be cleaned evenly and coated with release agent evenly.
Seven, safe and civilized construction:
1. Conduct safety education for all personnel entering the site construction, especially the outsourced personnel. To set up a safety management team, the responsibility for safety work should be implemented to people.
2, pump pipe rack should be built separately, shall not borrow beam, plate support.
3, wall, beam template work frame must be spread with springboard, hanging a safety net in the middle.
4. During the erection of beam and plate supports, there must be full-time quality inspectors, quality inspectors and on-site responsible division to supervise at any time.
5. Safety disclosure should be made before construction, and the safety officer should check all safety items.
6. The signalman and trench worker who cooperate with hoisting shall be fully equipped as required.
7. The holes in the structure must be blocked to prevent falling.
8. All personnel entering the construction site must wear safety helmets, and aerial work must wear safety belts.
9. Take effective safety measures for the mechanical and electrical equipment erected on the template.
10, aerial work, all kinds of accessories should be put in the toolbox or tool bag, to prevent falling.
1 1, when disassembling the template, someone should meet up and down, and the moving parts should be fixed firmly when disassembling.
12, when disassembling the template, board on a solid shelf to prevent overturning. When lifting the pre-assembled plate vertically, there should be at least two lifting points.
13. See the safety protection construction scheme for the stacking of large formwork.
14, when pre-assembling formwork or large formwork, hang up the hanging ditch, check whether all connectors are removed, and support demoulding and hoisting.
Template engineering construction scheme (2)
I. Overview of the Project
This project is a commercial and residential building project of Hongyang Garden in Tangshan City, located on the west side of Torch Road in Tangshan City. Prepared by Tangshan Hongyang Real Estate Development Company through bidding, Tangshan Guo Wang Construction and Installation Co., Ltd. won the bid. The construction period is 333 days, and it is required to start construction on June 10, 20**, and be completed and put into use on October 30, 20**. The project is designed by Tangshan Planning and Architectural Design and Research Institute, and the building plane is a 5-unit combined strip residential building. The building area is 16757.66M2 (including basement area of 23 10M2). The basement is one and a half floors, and the main body on the ground is six floors. The basement is 2.2M high, the first floor is 3.6M high, the second floor is 3.0M high, and the third to sixth floors are 2.9M high. Huxing combination is one staircase and two households, the first and second floors are commercial and the third to sixth floors are residential. The project is a frame structure. Template construction scheme is compiled according to Safety Inspection Standard for Building Construction (JGJ59-99), Safety Technical Specification for Fastening Steel Pipe Scaffolding for Building Construction (JJ130-2001) and Detailed Rules for the Implementation of Safety Inspection Standard for Building Construction in Hebei Province.
Second, the template installation overview
This project needs a large number of formwork, including composite steel formwork for columns, wooden formwork for the bottom of frame main girder and steel formwork for side formwork. Φ φ48mm steel pipe is used for the support, and the steel pipe conforms to the current national standards.
As for the standard of A3 steel, the square timber adopts 65 * 100 mm column formwork, which is fastened with steel pipes from top to bottom, so as to ensure that the formwork is not dismantled and the column axis is not displaced, and the column spacing is not more than 600mm, and it is fastened with short steel pipes. Beam slab is supported by φ48mm steel pipe, beam bottom formwork is made of wood formwork, and side formwork is made of small steel formwork. In order to ensure the section size of beams and columns, steel bars with a diameter of 6.5mm are installed in the beams and columns, and perforated tie rods are welded at both ends. The springing height of beam bottom formwork is 0.3%.
Third, the template preparation before installation
1. Before the template is installed, the project technical director shall make a written safety technical disclosure to the operation team leader, and then the operation team leader shall conduct safety technical disclosure and safety education for the operators. Relevant construction operators should be familiar with the construction drawing and template engineering construction design.
2, the construction site set up reliable measurement control points, meet the needs of template installation and inspection.
3. The templates and accessories used on site shall be checked item by item according to specifications and quantity, and those without repair shall not be used.
4, steel template before installation should besmear brushs release agent.
5. When the pillars of beam and floor formwork are supported on the soil ground, the ground should be leveled and compacted in advance, and the bottom plate of the column should be prepared.
6. The bottom surface of the formwork installation should be smooth and solid, and reliable positioning measures should be taken. Vertical formwork shall be embedded with supporting anchor bolts according to the requirements of construction design.
Four, template installation safety technical measures
1, template installation must be carried out in accordance with the template construction design, it is strictly prohibited to make any changes.
2, accessories must be installed firmly, under the pillar and brace. The bearing surface should be smooth and padded, and have enough stress area. Support should be concentrated on the outside steel stare blankly, embedded parts and reserved holes must be positioned accurately and installed firmly. The foundation formwork must be firmly supported to prevent deformation, and the bottom of the side formwork diagonal brace should be padded. The bottom surface of wall and column formwork should be leveled, and the lower end should be aligned with the positioning datum prepared in advance. When continuing to install templates on walls and columns, the templates should have reliable support points and correct their straightness.
3, the strength of the lower floor structure, when it can bear the weight of the upper template, support and new concrete, to, otherwise the lower floor structure support system can't be removed, at the same time, the upper and lower pillars should be in the same vertical line.
4, template and its supporting system in the installation process, must set up temporary fixed facilities, to prevent capsizing, after all the columns are installed, should be timely set up in the horizontal and vertical direction bracing, and fixed firmly with the column, when the height of the column is less than 4 meters, should set up two horizontal bracing, between two horizontal bracing, between vertical and horizontal bracing, and then every 2 meters high to add a horizontal bracing, and also need to add a bracing between horizontal bracing, support rod connection.
5, template installation must be carried out in accordance with the template construction design progress, it is forbidden to make any changes.
6, the strength of the lower floor structure, when can bear the weight of the upper template, support and new pouring concrete, otherwise the support system of the lower floor structure can't be dismantled, and the upper and lower columns must be on the same vertical line at the same time.
7, template and its supporting system in the installation process, temporary fixed facilities must be set up to prevent capsizing.
8. After the installation of all pillars, horizontal bracing and vertical bracing should be added in time along the horizontal and vertical directions, and fixed firmly with the pillars. Horizontal bracing should be set in the upper and lower directions, and between two horizontal bracing, bracing should be added in the vertical and horizontal directions.
9. The support upright post is set vertically, and fragile articles such as pad bricks are prohibited below. The vertical allowable deviation of 2M height is 15mm.
10, when the beam formwork support vertical pole adopts a single vertical pole, the vertical pole should be located in the center line of the beam formwork, and its eccentricity is not more than 25MM.
1 1. The four sides of the formwork and every four rows of support poles in the middle are provided with a longitudinal support, which is connected from bottom to top.
12, shuttering shall be carried out according to the construction technology, and the next working procedure shall not be carried out before the formwork is fixed.
13, when setting column formwork and beam formwork, you need to set up a facility floor. Scaffolding should be laid strictly, and protective railings should be set on the outside. It is forbidden to walk on column formwork and beam formwork, and climb up and down with the support of tie rods.
14. Before the wall formwork is installed with opposite bolts, the board surface should be tilted backward at a certain angle and braced firmly to prevent collapse. In the process of installation, support should be removed or added at any time to keep the wall formwork in a stable state.
15. When installing the wall formwork, start from the internal angle and external angle, and assemble in two directions perpendicular to each other. U-shaped teeth connecting templates should be installed alternately in front and back, and templates on both sides of the same wall should be combined at the same time to ensure the stability of template installation.
16, when the floor formwork is installed in place, it must be firmly supported, and the horizontal stare blankly under the plate is firmly connected with the support.
17, strong wind above level 5, formwork installation must be stopped.
18, after the template is installed, concrete can only be poured after inspection and acceptance, and the contents of the acceptance certificate should be quantified.
Five, template removal safety technical measures
1. Before form removal, it is necessary to confirm that the concrete strength meets the requirements, and it can only be carried out after the application for form removal is approved. When the concrete strength report does not meet the requirements, it is forbidden to dismantle the form in advance.
2. Before dismantling the formwork, the safety technical disclosure shall be made to the operation team, and a safety warning line shall be set within the operation scope and warning signs shall be hung. When dismantling the formwork, there shall be a special person (guardian) to guard it.
3. Sequence and method of form removal: according to the principle of supporting first and then removing, remove the non-bearing part first and then the bearing part, from top to bottom.
4. When dismantling the formwork, there should be special personnel to command and practical safety measures, and a work area should be set at the corresponding position. Non-operators are strictly prohibited from entering the work area.
5. Check whether the tools used are firm before work. Hands-on tools must be hung on the body with rope chains. Concentrate on your work to prevent nails from sticking your feet and falling from the air.
6. In case of gale of magnitude 6 or above, outdoor work at heights shall be suspended. In case of rain, snow and frost, the construction site should be cleaned first, and then the operation should be carried out when it is not slippery.
7. Dismantle the template with a long crowbar. It is forbidden for the operator to stand on the template being dismantled.
8. There are reserved holes in the floor slab and stair floor slab. After the formwork is removed, do a good job of safety protection railings at the corresponding parts at any time, or cover the holes with cover plates.
9, ripping clearance, will have activities such as template, tie rod, support fixed firmly, beware of sudden fall, collapse cuts.
10. When dismantling the foundation and basement formwork, check the formwork first. When unsafe factors such as soft and cracking are found in the earth wall, measures must be taken before people can work. Dismantled templates and supports shall not be piled up in the range of 1m at the top of the trough, and shall be transported with the dismantling.
1 1, when dismantling the formwork of plates, beams, columns and walls, attention should be paid to:
(1) When dismantling the formwork more than 2m, scaffolding or operation platform shall be erected, and the scaffolding shall be spread all over, and protective railings shall be set.
(2) It is forbidden to operate on the same vertical plane.
(3) Dismantle them one by one, and do not break them into pieces, pry them off or pull them down.
(4) When the bottom formwork of beam balcony floor is dismantled, temporary support shall be set to prevent the big formwork from falling.
(5) It is forbidden to stand on the cantilever structure and knock off the balcony bottom die.
12, everyone should have enough working faces, and when several people operate at the same time, they should clearly divide their work, unify their signals and proceed.
Six, template transportation, maintenance and storage
1, steel formwork transportation, different specifications of the template shall not be mixed, and effective measures must be taken to prevent the template from sliding.
2. After the steel formwork and fittings are dismantled, the bonding mortar shall be removed in time, and the deformed and damaged steel formwork and fittings shall be repaired and corrected in time, and mechanical shaping and cleaning shall be adopted.
3. Steel formwork that is not used for the time being shall be coated with release agent or antirust oil on the board surface, painted with antirust paint on the back, and stacked according to specifications.
4. The steel formwork shall be placed indoors or in an open shed, and the bottom of the formwork shall be greater than 100mm from the ground. When stacked in the open air, the ground shall be flat and solid, and the height shall not exceed 2m.
Seven. Design calculation book
Calculation of formwork and top bracing of rectangular beam
Beam length 6. 9 meters, the section size is 250 * 550 mm, 3.6m above the ground, the spacing of steel pipe jacking at the bottom of the beam is 600mm, the spacing of vertical side formwork is 600 mm, and Korean pine for wood: Fe =10n/mm2 Fv =1.44n/mm2.
f m = 13N/mm2
1. Floor calculation
(1) floor calculation
Bending strength checking calculation
Calculation of load borne by bottom formwork: Four parts of load should be considered in the design of bottom formwork of beam. The self-weight of formwork, the weight of fresh concrete, the weight of reinforcement and the load generated by vibrating concrete are all multiplied by the subentry coefficient 1.2, and the thickness of bottom formwork is 4 mm ..
Bottom die weight? 1.2×5×0.04×0.25 = 0.06 kn/m.
Concrete load? 1.2×24×0.25×0.55 = 3.96 kn/m.
Reinforcement load1.2×1.5× 0.25× 0.55 = 0.25kn/m.
Vibrating concrete load? 1.2×2.0×0.25 = 0.6 kn/m.
According to the Code for Construction and Acceptance of Concrete Structure Engineering, the design load value should be multiplied by the reduction factor v = 0.90, so q = 0.9× 4.87 = 4.38kn/m..
(2) check the bending bearing capacity of the bottom die
The spacing of top bracing under the bottom formwork is 0.6m, and the calculation diagram of the bottom formwork is a continuous beam with equal span and multiple spans. Due to the limited length of formwork, it can generally be calculated as a four-span continuous beam. Static calculation table shows:
L=0.6m？ L=0.6m？ L=0.6m？ L = 0.6m
mmax =-0. 12 lql 2 =-0. 12×4.38×0.62 = 0. 19 1kn·m
Check by the following formula
Mmax /W n≤kf m
mmax/wn=0. 19× 106/﹛250/(6×402)﹜=2.87n/mm2<； 1.3×13 =16.9 Newton/mm2
comply with the requirements
(3) Checking calculation of shear strength
Vmax = 0.620 QL = 0.620×4.38×0.6 = 1.63 kn
lmax = 3 VMAX/2bh = 3× 1.63× 103/(2×250×40)= 0.24n/mm2
kfv = 1.3× 1.4 = 1.82n/mm2 & gt； 0.24 N/mm2
comply with the requirements
(4) Deflection calculation
When checking deflection, the standard value of load is adopted, and the load of vibrated concrete is not considered.
Q' = 0.05+3.3+0.17 = 3.52kn/m.
wa=0.967×q'l4/ 100ei=0.967×3.52×6004/﹛ 100×9× 103×( 1/ 12)×250×403﹜=0.37mm
The allowable deflection is h/400 = 600/400 =1.5mm > 0.37 mm
comply with the requirements
2, the side template calculation
(1) lateral pressure calculation, beam side template strength calculation, should consider the load generated when vibrating concrete and the pressure of fresh concrete on the side of the template, and multiply it by the subentry coefficient 1. 2。
When using internal vibrator, the maximum lateral pressure of newly poured ordinary concrete acts on the formwork:
F = 0.22× 24× 200/20+15×1×1× (2) 0.5 = 42.66 kn /M2.
F = 24h = 24× 0.55 =13.2kn /M2
Whichever is smaller, F= 13.2KN/M2.
When vibrating concrete, the lateral pressure is 4KN/M2.
Total lateral pressure q1=1.2 (13.2+4) = 20.64kn/m2.
The linear load q = 0.6× 0.9q =11.15kn/m.
(2) Check the bending strength
According to the four-span continuous beam look-up table:
mmax =-0. 12ql 2 =-0. 12×8.36×0.62 = kn m =-0.486
The static sectional resistance moment of steel formwork is 5.94CM3
So mmax/wh = 253×103/5.94×103 = 81.82mm2.
The design value of bending strength of A3 steel is 200 N/mm2 >: 8 1.82N/MM 2.
comply with the requirements
(3) Checking calculation of shear strength
Vmax = 0.62 QL = 0.62× 1 1. 15×0.6 = 4. 15kn
τmax = 3V/2A = 3× 103/2× 1040 = 5.99n/mm2
The shear strength design value of A3 steel is125n/mm2 > 5.99 north latitude /MM2
comply with the requirements
(4) Deflection calculation
Q = 0.6× (13.2+4) =10.32kn/m.
wa = 0.967×ql4/ 100 ei = 0.967× 10.32×6004/ 100×2.06× 105×26.97×？ 104 = 0.24 mm
[W]= 450/400 = 1. 13mm & gt； 0.24 mm
3. Top bracing calculation
Steel stare blankly choose 48 x 3.5 mm diameter steel pipe, spacing of 0.6m, in the middle of the 3.6 m height set two horizontal support.
L0=3.6/3= 1.2m
I =(I/A)0.5 =( 12. 19× 104/4.89× 102)0.5 = 15.79mm
λ= L0/I = 1600/ 15.79 = 10 1.33
(1) strength checking calculation
It is known that n = 4.38/2× 0.6 =1.315kn.
n/AN = 13 15/4.89× 102 = 2.68n/MM2 & lt； 2 15N/MM2
comply with the requirements
(2) Stability checking calculation
Because λ= 10 1.33, the stability coefficient Ф = 0.628.
n/фA0 = 13 15/0.628×4.89× 102 = 4.28n/MM2 & lt； 2 15N/MM2
comply with the requirements
4, bolt shear strength calculation
n/2 A0 = 7.73×0.75/[2×(3. 14× 122/4]= 7.73×0.75/(2× 1 13)= 25.6n/mm2 & lt； Fv = 125 N/mm2
(4) Calculate the allowable load according to the most unfavorable factors of compressive stability.
N/xA+BMX/[rxWix( 1-0.8×N/NEx)≤f
N/(0.487×452)+( 1×24N)/{ 1. 15×3862.88×[ 1-0.8×(N/3862.88)]}≤f = 2 15N/mm2
The allowable load is n =13.2kn.
A- cross-sectional area of casing steel pipe (mm2) Look-up table A=452(mm2)
Ah—— Look-up table of cross-sectional area of intubation steel pipe Ak=357(mm2).
Stability coefficient of x- axial compression members
Slenderness ratio λ=UL/i2(L is the length i2 of steel column and the radius of gyration mm of casing)
Conversion coefficient U=( 1+h/2)0.5 h=I2 (cannula penetration torque) /I 1 (cannula penetration torque).
-Equivalent bending moment coefficient = 1.0
MX- eccentric bending moment value MX = n.e e = d1/2 = 48/2 = 24 mm.
Wix─- steel column sectional resistance moment (mm3)
E- elastic modulus of steel column (N/mm2) E=2.06× 105N/mm2.
D 1- casing diameter d 1=48mm.
D2- intubation diameter d2 = 43mm.
The calculation of other beam-column formwork and support is the same as the above method, and detailed calculation will not be made here.
FC- Design value of tensile strength of wood along grain
Fv- design value of wood shear strength along grain
FM- Design value of wood bending strength
Mmax- maximum bending moment w- net sectional resistance moment
Vmax- maximum shear stress τmax- maximum shear stress
Ω ── Deflection of flexural members? I── radius of gyration
η-slenderness ratio an- net cross-sectional area
Ф ── Stability coefficient of axially compressed members
1, stow-wood 50 thick and 200-300 wide 2, wooden wedge 3, horizontal brace 4, wood column (steel column) spacing 1.0m 5, beam steel side formwork 6, beam bottom formwork 7, wooden stare blankly (65* 100)8, and steel formwork 9 at the bottom of the slab.