A, structural design or construction problems
Cooperation between departments and professions
Problems 1: parapet, side wall of open caisson, roof skylight wall, etc. Most of them are brick or block walls built on reinforced concrete slabs, and the interface between masonry and concrete is prone to cracks, resulting in water leakage.
Solution: All the places where the building needs to be submerged are submerged with cast-in-place concrete. If there are no special requirements for buildings, the flooding height is 200.
Problem 2: The beam and slab concrete has different strength grades, which makes the construction inconvenient.
Solution: The strength grade of beam and slab concrete poured at the same time should be consistent.
Question 3: The post-pouring belt of the basement can not be poured until at least 60 days later, but the waterproofing of the basement exterior wall and the backfilling of the foundation pit need to be constructed first. How to deal with it?
Solution: At the post-pouring zone of the basement exterior wall, a high precast reinforced concrete slab is set on the outside and placed inside the waterproof layer of the basement exterior wall. Architectural design should consider the waterproof practice here, and structural design should consider blocking the backfill with plates before pouring the post-cast strip.
Question 4: Some wall battlements are too small to be built conveniently, and the quality cannot be guaranteed.
Solution: When the size of wall battlements connected with concrete walls and columns is ≤ 120× 120 or the length of one side is less than 120, cast-in-place concrete wall battlements should be adopted.
Cracks in cast-in-place concrete floor slab
Question 5: The roof slab concrete has a high strength grade and is prone to cracks and water leakage.
Solution: The concrete strength grade of the roof structure should be as low as ≤C25.
Question 6: The basement floor concrete has a high strength grade and is prone to cracks and water leakage.
Solution: For mass concrete with long construction period (such as basement floor and external wall, etc.). ), the late strength of concrete should be considered in the design, and the concrete strength of not less than 60 days can be used.
Question 7: The interface between the new and old concrete in the basement floor and the side wall post-pouring zone is prone to cracks and leakage often occurs.
Solution: The joint of post-cast strip should be made into tongue and groove; The main reinforcement should be disconnected at the post-cast strip; Adopt expansion water stop.
Problems When PVC electric pipes are embedded in cast-in-place concrete slabs, cracks often appear along the direction of the pipes.
Solution: When non-metallic pipes such as PVC are embedded in reinforced concrete slab, 300-wide φ1.0×10×/kloc-0 steel wire mesh is placed along the bottom of the slab (outside the main reinforcement at the bottom of the slab).
Question 9: At present, a large number of equipment and pipes are buried in the concrete slab of the front room of the elevator room, which causes structural hidden dangers and cracks.
Solution: For plates with many embedded pipelines (such as elevator foreroom in high-rise buildings), the thickness should be +30 according to the thickness required by structural design.
Question 10: Concrete slabs with waterproof requirements, such as roofs, have strict requirements on crack control, so how to control cracks?
Solution: anti-crack fiber is added to the concrete of roof slab structure with waterproof requirements. The added amount is provided by the bidding center or the general contractor, and the parameters of the winning product are determined by the design unit.
Prevent the first floor from sinking.
Problem 1 1: The first partition wall itself has settlement, and the wall has settlement cracks.
Solution: A reinforced concrete foundation beam or foundation should be set under the first partition wall. The partition wall should not be directly placed on the building ground, nor should the method of thickening the concrete cushion on the original building ground (Yuanbao foundation) be used as the partition wall foundation.
Question 12: outdoor steps, flower beds, etc. Sinking and deformation.
Solution: the design of foundation and foundation should be considered when designing outdoor accessories of buildings.
Problem 13: The backfill soil on the first floor of the room is thick, and the quality of backfill soil is difficult to guarantee.
Solution: When backfilling, the supervisor must be in place to strengthen quality control and self-inspection measures. On the premise of backfilling in strict accordance with the specification requirements, according to the actual situation of the project, the following reinforcement measures can be taken:
(1) When backfilling large granular materials with low cohesion such as sand, stone and sand, it will not be reinforced separately.
(2) When the backfill thickness is less than 500, it will not be reinforced.
(3) When the backfill thickness is 500≤ and 2000 ≤, and the long span of the ground is less than 3000, place φ6@200 bidirectional steel mesh at the bottom of the concrete cushion of the building ground, and anchor it or put it on the surrounding structure; When the short span of the ground is greater than or equal to 3000, in addition to adding steel mesh according to the above requirements, a ridge wall is added at the bottom of the cushion layer, and the edge length of the grid formed by the ridge wall and the surrounding structure is not more than 3000. The practice of ridge wall shall be issued by the design unit, and the material of ridge wall shall be masonry, and the supporting relationship with the upper concrete cushion shall be guaranteed.
(4) When the backfill thickness is greater than 2000, precast reinforced concrete or cast-in-place reinforced concrete floor slab should be adopted.
Cooperation between departments and majors due to design reasons.
Problem 14: sometimes the strength of partition walls and infilled walls is not good.
Solution: The strength grade of non-bearing wall materials should be indicated in the drawings.
Question 15: Who is responsible for the secondary design of steel structure and foundation treatment?
Solution: The general contractor is responsible for the secondary deepening design of steel structure and foundation treatment, and the design unit must fully cooperate to ensure the connection of work.
Second, the problems existing in the design of architectural drawings
Fire protection design
Problem 1: The fire lane is less than 4 meters wide, and there is no back yard or lane. Planting trees in the park will affect the fire-fighting vehicles.
Solution: According to the specification, the width of fire lane shall be implemented according to the specification. If the upper part of the fire truck returns to the parking lot, the structural design of the lower part must meet the traffic requirements of the fire truck. The general plan of the garden shall be reviewed by the architect and reported to the fire department for approval.
Question 2: the window opening area of the elevator front room is not 3 square meters.
Solution: According to the specification, if it is less than 3 square meters, a pressurized air supply shaft can be added.
Question 3: There is not enough fire separation between buildings.
Solution: Follow the specifications.
Question 4: The first floor of the stairwell is not separated from the basement.
Solution: Follow the specifications.
Question 5: The generator and fire pump were not in the first phase, which delayed the acceptance of the first phase.
Solution: In the first stage, we should consider improving the supporting facilities. If the skirt building is not decorated or temporarily not used, design the fire protection system first, and then accept it after the construction is completed.
Question 6: The fire pump room has no direct access to the safety exit.
Solution: Follow the instructions.
Common design problems and measures
roofing waterproof
Problem 1: The quality of waterproof material is unstable.
Solution:
(1) waterproof coiled material is selected, and its thickness is determined according to national specifications.
(2) For villas in the northern region, two coiled materials shall be waterproof according to the secondary waterproof grade.
Problem 2: The location of insulation layer is not clear.
Solution:
(1) The thermal insulation material is extruded polystyrene board.
(2) Do heat preservation first, then do waterproof, and do waterproof in the south, then do heat preservation.
Problem 3: The crack at the bottom of the top parapet leaks.
Solution: Make the concrete parapet less than 300mm. ..
Question 4: Water leaks around pipes, wells and flues protruding from the roof.
Solution: Around the pipes, wells and flues protruding from the roof, reinforced concrete waterproof anti-beam should be poured together with the roof structure. The elevation of the flat roof should be set at 250 mm above the highest completion surface, and the inclined roof should be set at 250 mm above the completion surface.
Question 5: The pipeline leaks from the floor and roof.
Solution: select and bury casing according to regulations; The casing shall be filled with asphalt hemp and waterproof ointment.
Question 6: There are two ways to design the construction method of Spanish roof tiles, one is hanging and the other is horizontal. Most of the roofs of villas that are hung and pasted have water seepage.
Solution: Change the horizontal pasting technology. If the roof slope is too steep, strengthen measures such as hanging net should be added in the horizontal sticking process, or the waterproof layer of coiled material should be thickened (more than 30mm) and then the hanging sticking process should be adopted for construction. The specific approach is mainly based on the regional norms of each company.
Question 7: Some villa units are designed with hidden gutters. However, due to the lack of any strengthening measures in the design, many roofs have culvert leaks.
Solution: unify into an open ditch.
Indoor waterproofing
Problem 1: There is no side drainage in the caisson toilet, which is easy to cause water accumulation in the caisson, resulting in water seepage. When preparing to supplement the side drain pipe, the riser cannot be added because the tube well area is not enough.
Solution: add lateral floor drain, and the tube well in the northern area can be appropriately increased due to installation difficulties.
Problem 2: The caisson shaft is installed in waterproof casing. When the shaft is installed in the toilet, the thickness of the shaft wall (inside the caisson) is usually only 8~ 10cm, so it is impossible to install the waterproof casing properly.
Solution: It is suggested that the wall thickness of caisson pipe should be 12cm, and it is a steel-concrete structure. The caisson is overhead and not backfilled.
Question 3: The bathroom wall is leaking.
Solution: The flexible waterproof height is 300mm, and waterproof mortar is used for the above parts. Concrete return at the root of wall in Beijing area 120mm.
Question 4: When installing toilet equipment, it can't be fixed and it is easy to leak water.
Solution: It is suggested that all bathroom walls should be made of solid bricks.
Question 5: The indoor water supply pipe is tied.
Solution: Try to avoid the door when the plumbing pipe goes through the wall, and go through the wall by the door. Shearing walls are reserved with sleeves.
Exterior wall waterproofing
There is a problem 1: cracks in the external wall are leaking.
Solution: The external wall is cement mortar mixed with anti-crack fiber.
Question 2: Wall materials.
Solution: When autoclaved aerated concrete blocks are used, corresponding anti-crack measures should be added (such as hanging nets on internal and external walls and adding anti-crack fibers to plastering layer).
Problem 3: lintel and window sill are leaking.
Solution: The window lintel should have drip line; The outer window sill should be lower than the inner window sill, and the drainage slope should be sufficient; The lower frame of aluminum alloy window should have drainage structure; The outside of aluminum alloy window shall be sealed with waterproof glue. Strictly implement the construction specifications.
Question 4: There are many GRC external decorative components, and some GRC legs of external walls are not designed with overhangs, which is easy to cause water leakage at the junction between GRC components and external walls, and cracks are also easy to appear at the junction between GRC components.
Solution:
(1) Minimize the use of GRC and reduce the style of GRC lines.
(2) After selecting the supplier, provide the installation node to the design unit in time. Waiting for design confirmation
The rear can be installed.
(3) The design institute should pay attention to the different materials of drainage slope, drip tank and decorative line in the drawings.
Mark the anti-crack measures of lap joint.
(4) The setting board of the design department should consider the problem of line flooding and water seepage.
(5) The engineering department should carefully review the construction scheme of decorative lines.
Basement waterproofing
Question 5: The quality of waterproof material is not up to standard.
Solution: The coiled material is used for waterproofing, and the waterproofing grade and design should meet the national standards.
Common faults and solutions of building joints
Doors, windows and railings
There is a problem 1: wooden doors for ceiling doors are not allowed by the specifications.
Solution: the wooden door outside the sky.
Question 2: Due to cost factors, Party A will cancel the steel frames of some building doors and windows. However, after the steel frame is cancelled, the openings of doors and windows will not be closed in time after the structure is completed, which will greatly affect the progress of the project and easily cause pollution and damage to the aluminum frame.
Solution: After the general contractor calculates the cost, it will be reported to the headquarters for approval.
Question 3: the elevator is on the first floor. When the wind is strong in autumn and winter, the elevator hall door can't be closed in place, and it needs external force to close it; In design, the elevator in the lobby should be sheltered from the wind, and the elevator door can be opened and closed freely. For example, the elevator in the tower of oasis community will appear this phenomenon when it opens the door in the lobby.
Solution: agree and adopt its practice.
railing
Question 7: The details such as wrought iron, iron flowers and protective railings are uneven and cannot be used as the basis for construction.
Solution:
(1) Data and samples are provided by the construction unit and selected by the designers.
(2) Design details of the design company.
Question 8: The railing height is less than 1 100.
Solution: Follow the instructions.
Question 9: The embedded parts of balcony railings can't be reserved during the main construction because the railings have no vertical pole spacing, and expansion screws are not allowed to be used during installation, which will cause the structure to be knocked out.
Solution: Design and determine the spacing and details.
Problem 10: The paint of galvanized steel pipe on balcony falls off and rusts.
Solution: The design must be clear about the matching paint (enamel).
There is a question of 1 1: the setting of window protective railings on the windowsill of indoor bay windows.
Solution: The standardization design team makes the standard drawing in a unified way.
Question 12: according to the residential design code, when the clear height of the window sill of the external window is less than 0.8m from the floor and the ground, protective facilities should be set up, and all windows with the height of the window sill less than 0.8m should be provided with safety barriers. At present, the guardrail height of the bay window is low, and children are easy to break the glass and fall down. It is suggested to increase the height of guardrail.
Solution: Follow the instructions.
Problems: 13: protective railings are installed between the roof and the platform unit to prevent outsiders from passing through and ensure safety; Because the sliding door of the window can't be closed and there is no anti-theft device, many buildings appear from the sliding door of the owner's platform and enter the room, resulting in theft.
Solution: Agreed, fully considered in the design.
Question 14: a fence should be added beside the landscape pool in the community to prevent children and the elderly from slipping and falling.
Solution: Don't adopt its practice.
Decorative details
There is a problem 1: the facade of the tube well in the walkway is tiled.
Solution: The decoration professional will do the details and determine the color.
Problem 2: The seam between the indoor wooden cabinet and the wall is not handled properly.
Solution: through decoration.
Problem 3: the specifications of bathroom and kitchen wall tiles are too large, which are easy to empty and wear.
Solution: It is suggested that the wall tiles should not be too big, not more than 500×500, and vitrified tiles should not be used.
Question 4: Tilt stickers are used for wall and floor tiles, which are very costly.
Solution: In the handover standard, it is clear that diagonal stickers should not be used as much as possible.
Problem 5: The cabinet is unqualified, which leads to the unqualified acceptance of the gas project.
Solution: Implement the specification. During design and construction, exhaust holes are reserved in the closed space where gas hoses and gas meters are placed, and exhaust plates are installed.
Question 6: The elevator threshold should be higher than the ground, and there should be a reasonable slope between the threshold and the ground to prevent water from flowing backwards into the elevator shaft and affecting the elevator operation.
Solution: agree and adopt its practice.
Roofing engineering
Problem 1: The slope of the sloping roof is too large.
Solution: Try to slow down the slope as much as possible without affecting the design effect.
Problem 2: Single reserved heating pipe: Due to the limitation of floor thickness, the reserved heating pipe is higher than the intersection of concrete protective layer pipes, so the floor has to be demolished.
Solution: Leave the heating pipe on and give the marketing department a reasonable solution.
The explanation.
Question 3: Whether to adopt concrete trench type finished water collection system.
Solution: combined with local use of facade.
Question 4: The construction unit often puts forward the change requirements of roof slope-finding materials.
Solution: Han Jian proposed several specific practices, which were selected by the design company.
Plastering engineering
The existing problem is 1: the partition walls of terraces of multi-row villas are "torn" due to the influence of rain and dust and hung up.
Solution: drip line should be added to the design.
Question 2: Our company's basement ceiling design method is basically shed 6 12J 1- 1 atlas, and 2mm waterproof mortar is scraped directly on the insulation board, which is likely to cause quality hazards (only used in Beijing).
Solution: It is necessary to set grid cloth, and build indoor and underground thermal insulation ceiling of new project: refer to 88J2-9 and shed 26-W. ..
Question 3: The indoor ceiling of our company generally adopts the method of plastering cement lime mortar in shed 8B and shed 9B of 88J 1- 1 Atlas. This method is rarely used now, and it is easy to cause quality and safety accidents.
Solution: Smooth with putty and cancel plastering.
Question 4: Whether the construction method of stone paving for external walls in northern China is combined with the thermal insulation method.
Solution: Agreed.
Question 5: The floor and floor of the water pump room that has been delivered are all damaged by cement wool. The design should be carried out according to the standard of issuing the hygiene license for secondary water supply by the health and epidemic prevention station (laying walls, floors and floor tiles in the drainage ditch), so as to avoid affecting the normal water supply and polluting the facilities of the water pump room when the machine room is rebuilt again.
Solution: agree and adopt its practice.
Wall engineering
Question 1: Some basements are also designed as lightweight partition boards. However, since the floors of basements (especially the basement level) are all higher than 3.3 meters, the height of lightweight partition boards should not exceed 3.3 meters, otherwise it will cause the danger of cracks or even fractures.
Solution: It is suggested that the basement partition wall be changed into block.
Problem 2: Some shear walls are too small to install door covers.
Solution: The future crib should not be less than 10 cm (but the size required by the structure should be guaranteed).
Problem 3: The distance between the shear wall and the window side is too small, but the masonry structure is still designed on the drawing, which increases the construction difficulty and is prone to cracks.
Solution: Look at the structure.
Question 4: GRC lightweight partition board is cracked.
Solution: In addition to laying glass fiber grid cloth to strengthen the joints, glass fiber grid cloth should be laid fully.
Question 5: The size of electrical embedded drawings should be kept as far as possible, such as distribution boxes. Because sometimes the bidding time will lag behind the construction progress, if the equipment size of each manufacturer is comprehensively considered and the corresponding reserved size is not provided, it will cause waste.
Solution: Agreed.
Floor structure
Problem 1: The original drip board of the non-open caisson bathroom is 3cm, which makes the height difference between the inside and outside of the bathroom insufficient, which makes it difficult to find the slope of the bathroom floor, especially at the entrance, which is easily higher than the outdoor floor. If we want to ensure the height difference, it will easily lead to insufficient slope and water accumulation.
Solution: The floor next to the floor drain can be lowered again, and the details are marked in the structural drawing.
Problem 2: Single reserved heating pipe: Due to the limitation of floor thickness, the reserved heating pipe is higher than the intersection of concrete protective layer pipes, so the floor has to be demolished.
Solution: Leave the heating pipe on and give the marketing department a reasonable explanation.
component
Question 1: The air conditioning position of each room should be considered in the residential hall to facilitate the installation and maintenance of the outdoor unit. The frame should be large in volume, and it can also be equipped with high-power outdoor units. The platforms of the indoor unit and the outdoor unit are too far apart to prevent the outdoor connecting pipes from being too long and affecting the beautiful facade of the building.
Solution: Agreed, fully considered in the design.
There are two problems: when designing the flue, we should consider the avoidance of pipes in the kitchen; Current management
Some buildings have pipes passing through the air outlet of flue, so it is impossible to install exhaust pipes. Such as: Dijing, Zhongjun District Huxing have this phenomenon.
Solution: Agreed, fully considered in the design.
Question 3: The platform of the villa should reserve space for solar water heaters. Nowadays, more and more owners in the management community install solar water heaters, which is also in line with the national energy-saving trend. For the convenience of management, it is suggested to consider the unified placement of aircraft seats in the design.
Solution: Don't adopt its practice.
Question 4: Load-bearing hooks should be reserved in the machine room (such as embedded hooks in the suspended ceiling of water pump room, fire pump room, heating room, boiler room and elevator room). ) to facilitate the disassembly and maintenance of heavy machinery and equipment.
Solution: agree and adopt its practice. Civil engineering design conditions are provided by equipment specialty, and drawings are drawn by structure specialty.
Question 5: diagonal decorative clips and cheap floor springs are used for the glass doors in the lobby of each building, which is not suitable for the windy environment in Beijing and the damage rate reaches 60%. The design scheme similar to McDonald's door should be adopted, with both frame glass doors and high-quality door closers.
Solution: agree and adopt its practice.
Question 6: The distribution room is now in the basement, and the floor is higher than the floor of the corridor or waterproof steps are made at the indoor entrance.
Solution: agree and adopt its practice.
Question 7: The design of air conditioning orifice plate is unknown.
Solution:
(1) The air conditioning hole on the balcony of the living room conflicts with the balcony downspout, and the distance between the hole and the wall must be 200.
(2) When the air conditioner goes out of the balcony or kitchen, the distance from the wall is 100, and the turning radius is not enough.
(3) The width of the air-conditioning board in the living room is 1000, which should be ≥ 1 100.
Question 8: The design of gas water heater is unknown.
Solution:
(1) The 800-wide wall for hanging the water heater should be built with solid walls.
(2) When installing a gas water heater on the balcony, it is necessary to hang the solid wall of the water heater 600 wide.
Question 9: Furniture layout
(1) Every room needs to be decorated (the drawings of workers' rooms and sundries are often missed).
(2) The kitchen stove, sink and smoke exhaust shaft are randomly arranged.
Solution: the design is fully considered.
Problem 10: The reserved hole is incomplete.
Solution:
(1) The architectural drawing shows the positive pressure air supply outlet of the stairwell.
(2) The reserved holes of the strong and weak current box must be marked.
(3) All kinds of drainage pipes and rainwater pipes must be marked.
(4) The straight hole of gas water heater must be marked.
Question 1 1: When going out in duplex, the indoor floor height of the duplex lower floor is uncertain.
Solution: When the compound exit, the floor height of the compound lower floor should be 3.2m ..
Question 12: The side wall of bay window sill 100 should be concrete wall, and the picture is dark black.
Solution: Agreed.
Existing problems 13: transfer floor
(1) The caisson in the bathroom is prone to problems, and the transfer beam deviates from the bathroom wall.
(2) Various sewer pipes conflict with transfer beams.
(3) When there is an outdoor terrace, we should consider solving the problem of indoor height difference.
Solution: the design is fully considered.
Question 14: Garden roads in residential areas are easily polluted by green water because kerbs are flush with the road surface and green space is higher than the road surface. It is suggested that kerbs should be improved in design.
Solution: agree and adopt its practice.
Question 15: The elevator lobby of the underground garage should be decorated together with the lobby on the first floor, and the garage and underground lobby should be clean and bright, consistent with the overall grade of the community.
Solution: agree and adopt its practice.
The existing problems are 16: the garage ramp is long, with large area and few ditches; When the rainy season comes, it is easy to cause rainwater to flood into the garage.
Solution: The design should consider adding a ditch or a sun shed.
Third, other common drawing errors
1, the waterproof problem of underground engineering is often easily overlooked, and the waterproof practice of underground engineering depends on the level of groundwater level.
2. Extending to the cable trench, waterproofing is often forgotten, and it is not enough to do internal waterproofing in areas with high groundwater level.
3. Anti-corrosion engineering is also sensitive to water. Without waterproofing, the adhesion between the anticorrosive surface and the substrate is not good and it is easy to fall off.
Although the ditch of the building is small, it can't be ignored. Ditch cover plate is not chosen at random, but depends on the load. In the past, the common cover plate was used in the project, and finally the truck was loaded. The heavy cover plate with load-bearing capacity should be selected, and the angle steel should be buried under the cover plate for reinforcement, and the steel bar should be used for reinforcement when crossing the trench.
5, distribution room doors and windows.
In general, there must be at least one large door to enter the distribution cabinet. Electrical professional requirements are generally not less than 1.2m wide and x2.4m high. It is suggested that the door should be 1.5mx2.7m, and the door should be detachable, so that when the initial installation and subsequent maintenance need to get in and out of the distribution cabinet, the middle bracket will be removed and people will generally leave. Try not to make a door with a height of 2.4m On the one hand, it sometimes fails to meet the installation requirements, because the clear height may not be enough after the door frame is removed. On the other hand, if a 2.4m-high door leaf is used to install cabinets, especially steel doors, it is heavy, inconvenient to open and the door shaft is easy to break. Electrical majors sometimes forget to raise the requirements of door height, so we need to confirm with them in time according to our experience to avoid problems in installation in the future.
The length of the distribution room is generally more than 7m, and two evacuation doors should be set. If it exceeds 60m, an exit should be added.
The height of the window sill of the high-voltage distribution room shall not be lower than 1. 8m fixed windows and low-voltage power distribution room should be equipped with sand fan opening windows, which cannot be opened into ordinary windows.
The doors of power distribution and dangerous laboratories are required to be open outside, and many people didn't pay attention to it when designing. It's all in the power distribution specification.
The outdoor cable trench shall be provided with a sump, and the trench bottom shall be inclined from the sump.
For power distribution, the indoor and outdoor height difference is greater than or equal to 600 in case of danger (heavier than air, with the possibility of condensation of explosive dangerous gas).
For the door between two power distribution devices, it should be opened to the side with low risk. Article 6.2.2 of Code for Design of Substations below 10KV (GB50053-94) When there is a door between adjacent power distribution rooms, the door should be able to be opened in both directions.
6, residential bay window to structural lifting plate size
Generally, the window size we mark is the size of the hole, and the bay window should be completely kept at the hole, so the window should be fixed at the outer edge of the hole, and the distance between the centers of the windows should be greater than the size of the hole. However, when we mark the window size in the plan, we still need to mark the size of the hole, and the size of the hole only reflects the actual size of the window in the facade development. Because the window is fixed on the outer edge, we should pay attention to the size of the cantilever plate when making conditions for the structure, which is generally 80- 100 per side (specifically determined according to the selection of window frames).
7. About the width of the door.
Many architectural designs require that the width of the door is not the width of the hole.
Regardless of the change of concrete structure.
Regardless of the construction factors and materials (for example, some designers design 10cm portal crib at the concrete column, but there is no requirement for pouring concrete, and some are only 6cm, so how to build bricks).
Classifying commercial buildings and complex buildings with a building area of more than 1 000 square meters and commercial and residential buildings with a building area of more than 24 meters as second-class high-rise buildings leads to a series of mistakes, such as the division of fire protection zones, the setting of evacuation stairs and the configuration of corresponding fire control facilities. Such mistakes are almost disastrous and must be paid attention to.
When building the master's house surface, when the distance between the parapet coping and the completed roof surface is less than or equal to 0.45 m and the coping width is greater than or equal to 0.22 m, the height of the railing should be calculated from the top surface of the treadable part.
Generally, if the parapet is a brick wall, the concrete coping is generally 80% wider than the wall and easily exceeds 0.22m m. At this time, we must pay attention to calculating the distance from the coping surface to the finished roof surface when we are at the height of the railing.
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