Cooperation between departments and specialties (4 main issues)
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.
Solving cracks in cast-in-place concrete floor slab (six difficult problems)
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 pipelines embedded (such as the elevator lobby of high-rise buildings). ), the thickness should be 30 according to the structural design requirements.
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.
Preventing the first floor from sinking (three major problems)
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 φ 6 @ 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.
Second, the problems caused by design reasons
Cooperation between departments and specialties (two main issues)
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.
Six problems in fire protection design
There is a problem 16: the fire lane is less than 4m wide, and there is no parking lot and driveway. Planting trees in the garden affects 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 17: The window opening area of the elevator front room is less than 3m2.
Solution: According to the specification, if it is less than 3m2, a pressurized air supply shaft can be added.
There is a problem 18: the fire separation between buildings is not enough.
Solution: Follow the specifications.
Question 19: The stairwell on the first floor is not separated from the basement.
Solution: Follow the specifications.
Question 20: 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.
Problem 2 1: the fire pump house does not go directly to the safety exit.
Solution: Follow the instructions.
Third, the design of common faults and measures
Seven problems of roof waterproofing
Question 22: The quality of Guangzhou 9 1 1 waterproof material is unstable.
Solution:
1) Select waterproofing membrane, and determine the thickness according to national specifications.
2) For villas in the northern region, according to the secondary waterproof grade, two coiled materials are used for waterproofing.
Question 23: The location of insulation layer is not clear.
Solution:
1) adopts extruded polystyrene board insulation material.
2) The northern region shall be insulated first, then waterproof, and the southern region shall be waterproof first, then insulated.
Question 24: The cracks at the bottom of the top parapet are leaking.
Solution: Make the concrete parapet less than 300mm. ..
Question 25: Leakage 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 sloping roof should be set at 250 mm above the completion surface.
Question 26: The pipes are leaking 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 27: There are two construction methods for roof tiles in Spain, one is hanging and the other is lying. 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. Tianjin refers to nodes 2-5.
Question 28: Some units in the villa are designed with hidden gutters, but many roofs are leaking because no strengthening measures were taken during the design.
Solution: Unified change to open ditch, using 2-5 nodes.
Five problems of indoor waterproofing
Question 29: There is no side drainage in the caisson toilet, which is easy to cause water accumulation in the caisson and form a hidden danger of 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.
Question 30: 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, Shanghai-Nanjing steel structure should be adopted, caisson should be overhead and not backfilled.
Question 3 1: 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 32: 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.
Problem 33: 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.
Five topics on external wall waterproofing
There is problem 34: leakage of cracks in the external wall.
Solution: The external wall is cement mortar mixed with anti-crack fiber.
Question 35: Wall materials.
Solution: Guangzhou is allowed to try autoclaved concrete blocks with air, but corresponding anti-crack measures should be added (such as hanging nets on internal and external walls and adding anti-crack fibers to plastering layer).
Question 36: The 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 37: 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. Can be installed only after the design is confirmed.
3) The design institute shall mark the drainage gradient of decorative lines, drip tanks and anti-cracking measures for overlapping of different materials in the drawings.
4) The plate setting of the design department should consider the problems of line flooding and water seepage.
5) The engineering department shall carefully examine the construction scheme of decorative lines.
Basement waterproofing
Question 38: 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.
Four, the common faults of building nodes and solutions
Doors, windows and railings (1 1)
Question 39: Wooden doors are used for ceiling doors, which is not allowed by the code.
Solution: the wooden door outside the sky.
Question 40: Due to cost factors, Party A plans to cancel the steel frames attached to some building doors and windows. However, after the steel frame is cancelled, the openings of doors and windows cannot be closed in time after the structure is completed, which has a great impact on the progress of the project and is easy to pollute and damage the aluminum frame.
Solution: After the general contractor calculates the cost, it will be reported to the headquarters for approval.
Question 4 1: The elevator is on the first floor. When the wind is strong in autumn and winter, the elevator hall door cannot be closed normally, 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.
Solution: agree and adopt its practice.
Question 42: The details of railings, wrought iron, iron flowers and protective railings are not uniform and cannot be used as the basis for construction.
Solution:
1) is provided by Han Jianti's wrought iron flower detail gallery and selected by designers.
2) Design details of the design company.
Question 43: The railing height is less than 1 100.
Solution: Follow the instructions.
Question 44: 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, resulting in the structure being knocked out.
Solution: Design and determine the spacing and details.
Question 45: The paint of galvanized steel pipe on balcony falls off and rusts.
Solution: The design must be clear about the matching paint (enamel).
Question 46: The setting of window railings for indoor floating windowsills.
Solution: The standardization design team makes the standard drawing in a unified way.
Question 47: According to the residential design code, when the clear height of the outer window sill from the floor and the ground is less than 0.8m, protective facilities should be set up, and all open windows with the sill height less than 0.8m should be provided with safety guardrails. 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.
Question 48: There are protective railings 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 49: A fence should be added next to the landscape pool in the community to prevent children and the elderly from slipping and falling.
Solution: Don't adopt its practice.
Six problems of decoration details
Question 50: The front of the sidewalk tube well is tiled.
Solution: The decoration professional will do the details and determine the color.
Question 5 1: the joint between the indoor wooden cabinet and the wall is not handled properly.
Solution: through decoration.
I believe that after the above introduction, everyone has a certain understanding of it. Welcome to Zhong Da for more information.
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