What are you afraid of when you understand these four major problems in construction engineering

Solutions: the joint of post cast strip shall be made into groove; the main reinforcement shall be disconnected at the post cast strip; expansion shall be adopted Waterstop.

solution: the design of foundation and foundation shall be considered in the design of outdoor accessories.

(3) When the backfill thickness is ≤ 500 and ≤ 2000, and the ground long span is less than 3000, it shall be placed at the bottom of the concrete cushion made on the building ground φ 6 @ 200 two-way reinforcement mesh, which shall be anchored or placed on the surrounding structure; If the ground short span is ≥ 3000, in addition to adding reinforcement mesh according to the above requirements, a ridge wall shall be added at the bottom of the cushion, and the side length of the grid formed by the ridge wall and the surrounding structure shall not be greater than 3000.

Existing problem 7: cracks are easy to occur at the interface between the old and new concrete of basement floor and side wall post cast strip, and leakage often occurs.

The partition wall shall not be placed directly on the building ground, and the concrete cushion in the original building ground shall not be thickened (Yuanbao Foundation) as the foundation of partition wall.

The method of ridge wall shall be issued by the design unit.

If the upper part of the fire truck return yard is made into a lawn, the substructure design must meet the traffic requirements of the fire truck, and the general drawing of the garden shall be reviewed by the architectural designer and reported to the fire department The door passes.

5: the strength grade of roof slab concrete is high, which is easy to crack and water leakage.

Existing problem 4: the size of some wall stacks is too small to facilitate masonry and the quality is not guaranteed.

Solutions: implement the specifications, and the width of the fire lane implements the specifications.

6: the strength grade of basement floor concrete is high, which is easy to crack and water leakage.

The waterproof practice at this place shall be considered in the architectural design, and the slab shall be used to block the backfill before the post cast strip is poured in the structural design.

Solution: mass concrete with long construction cycle (such as basement floor, exterior wall, etc.), the late strength of concrete should be considered in the design, and the concrete strength of no less than 60 days can be used.

Solution: cast-in-situ concrete flashing is adopted for all buildings where flashing is required, and the flashing height is not specified if the building has no specific requirements , press 200 high.

Problem 8: when PVC pipes are embedded in the cast-in-situ concrete slab, cracks often appear along the pipeline.

Cracks are easy to form at the interface between masonry and concrete, resulting in water leakage.

Solution: at the post cast strip of the basement exterior wall, a full-height precast reinforced concrete slab is set on the outside, which is placed on the inner side of the waterproof layer of the basement exterior wall.


(2) When the backfill thickness is less than 500, no additional reinforcement is required.

Solution: it shall be implemented according to the specifications, and pressurized air supply shaft can be added if it is less than 3M2.

Departments causing problems due to design Interprofessional cooperation (2 major problems) existing problem 14: sometimes the strength of partition wall and infilled wall is not good.

The addition amount shall be provided by the bidding Center or the general contractor, and the winning product parameters shall be determined by the design sheet Bit determination.

Problems caused by construction departments Interprofessional cooperation (4 major problems) existing problem 1: parapets, side walls of toilet tube wells, roof skylight walls, etc.

Existing problem 12: settlement and deformation of outdoor steps, flower beds, etc.

Existing problem 15: who is responsible for the secondary design of steel structure and foundation treatment.

Solution: the strength grade of roof structure concrete shall be ≤ C25 as far as possible.

There are problems in preventing the first floor floor from subsidence (3 major problems).

Existing problem 9: at present, a large number of equipment pipelines in the front room of the elevator room are buried in the concrete slab, resulting in structural hidden dangers and cracks.

Problem 3: the post pouring belt of the basement can be poured at least 60 days later, but the waterproof and foundation pit backfilling works of the outer wall of the basement need to be constructed first.

(4) When the backfill thickness is more than 2000, precast reinforced concrete or cast-in-situ reinforced concrete ground shall be used.

Solution: the strength grade of wall material of non load-bearing wall shall be indicated in the drawing.

Solution: reinforced concrete foundation beam or foundation shall be set under the first floor partition wall.

Solution: during backfilling, the supervisor must be in place and strengthen quality control and self inspection measures On the premise of backfilling in strict accordance with the specification requirements, the following reinforcement measures can be taken according to the actual engineering conditions: (1) when backfilling sand, stone, sand and other low cohesion and large particle size materials, no additional reinforcement is required.

are mostly brick or block walls built on reinforced concrete slabs.

Solution: add crack resistant fiber into the concrete of roof slab structure with waterproof requirements.

Existing problem 2: the strength grade of beam and slab concrete is different, which is inconvenient for construction.

How to deal with it.

11: the first floor partition wall itself settles and the wall body has settlement cracks.

Fire protection design [6 major problems] problem 16: the fire lane is not 4m wide, there is no return yard or return lane, and planting trees in the garden affects the fire vehicles.

Existing problem 18: the fire separation between buildings is not enough..

Lifting Anchor

Existing problem 17: the window opening area of the elevator front room is not enough 3M2.

Existing problem 10: the concrete slab with waterproof requirements such as roof has strict requirements on crack control, how to control the crack.

Existing problem 13: the backfill on the ground of the first floor of the room is thick, and the backfill quality is not easy to guarantee.

Solution: when PVC and other non-metallic pipes are embedded in the reinforced concrete slab, 300 wide pipes shall be placed along the pipeline at the bottom of the slab (outside the main reinforcement at the bottom of the slab) φ one × ten × 10 steel wire mesh.

The material of ridge wall shall be masonry, and the supporting relationship with the upper concrete cushion shall be guaranteed.

Solution: the secondary deepening design of steel structure and foundation treatment shall be completed by the general contractor, and the design unit must be fully responsible Cooperate with each other to ensure the connection of work.

Solve the problem of cracks in cast-in-situ concrete floor slab (6 major problems).

Solution: the size of wall stack connected with concrete wall and column shall be ≤ 120 × 120 or when the length of one side is less than 120, cast-in-situ concrete wall stack shall be adopted.

Solution: the strength grade of beam and slab concrete poured at the same time shall be consistent.

Solution: plates with many embedded pipelines (such as the elevator lobby of high-rise buildings), the slab thickness should be + 30 as required by the structural design.


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