1
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The two-way cross slope should be made in the urban road subgrade filling, the general soil filling cross slope should be 2% ～ 3%, and the low permeability soil filling cross slope should be 4%
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2
. 
The masonry culvert should be backfilled after the masonry mortar strength reaches ﹥ 5MPa and the prefabricated cover plate is installed; for the cast-in-place reinforced concrete culvert, the chest backfill should be carried out after the concrete strength reaches ﹥ 70% of the design strength, and the backfill above the roof should be carried out after reaching the design strength
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3
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The construction of lime stabilized soil materials for urban roads should be completed 30-45 days before winter, and the construction of cement stabilized soil materials should be completed 15-30 days before winter
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4
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The compactness of graded crushed stone for urban road should not be less than 97% for base course and 95% for subbase course
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5
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When filling the old asphalt pavement for urban roads, the pits should be controlled according to the elevation and paved in layers, and the maximum thickness of each layer should not exceed 10cm
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6
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The mixing time of urban road asphalt mixture should be determined by trial mixing, and the degree of asphalt evenly coated aggregate should be considered
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7
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After the construction of urban road cold asphalt mixture pavement, the traffic should be closed for 2 ~ 6h, and the early maintenance should be done well
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At the initial stage of opening traffic, the speed shall not exceed 20km / h, and it is not allowed to brake or turn around on it
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8
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After the asphalt penetration surface and surface treatment surface of urban road are rolled and shaped, the traffic should be opened orderly and the speed should be controlled
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When oil spill is found after opening traffic, caulking material shall be sprinkled
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9
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The compressive strength of cement concrete precast sidewalk blocks for urban roads should meet the design requirements, and should not be lower than 30MPa when not specified in the design
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The surface of the block shall be smooth, rough, with clear lines, neat edges and corners, and there shall be no honeycomb, exposed stone, peeling and other phenomena; the color of the color road brick shall be uniform
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10
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The backfill around rainwater branch pipes and inlets of urban roads shall be compact
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The rainwater branch pipe in the road base should be encased with 360 ° concrete, and the traffic should not be released until the encased concrete reaches 75% of the design strength
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11
.
The top of cofferdam should be 0.5-0.7m higher than the maximum water level (including wave height) that may occur during construction
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12
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When the caisson is raised, the top of the caisson shall not be less than 150cm above the water surface and 50cm above the ground
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13
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It is not allowed to use soil containing impurities, humus or frozen soil blocks for abutment back filling, and permeable soil should be used
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14
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The precast pedestal of urban bridge engineering shall be firm without settlement, the surface of pedestal shall be smooth and flat, the allowable deviation of flatness in 2M length shall be 2mm, and expansion joint shall be set when the temperature changes greatly
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15
.
When the construction support is set up for the steel-concrete composite beam of urban bridge, the construction support can be unloaded only after the concrete strength meets the design requirements and the prestressed tension is completed
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16
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During the construction of cable-stayed bridge, it is necessary to monitor the cable force, elevation of main girder, internal force of tower and girder and displacement of cable tower in each construction stage of main girder, and timely feed back relevant data to the design unit to analyze and determine the cable tension value, main girder alignment, elevation and displacement control value of cable tower in the next construction stage until closure
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17
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In the construction process of suspension bridge, the structural alignment and internal force of the completed bridge should be monitored in time to ensure that it meets the design requirements
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18
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The carcass materials of the coating waterproof layer of urban bridge deck shall be lapped along the flow direction, the lap width of the long side shall not be less than 50 mm, the short side shall not be less than 70 mm, and the lap joint of the upper and lower carcass shall be staggered by 1 / 3 width
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19
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When the city bridge is poured on the movable formwork, the length of the formwork must meet the requirements of sectional construction, and the working joint of sectional pouring should be set at or near the zero bending moment point
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20
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Cantilever construction of beam sections on both sides of bridge section shall be symmetrical and balanced
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The balance deviation shall not be greater than the design requirements
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When pouring concrete with cantilever, it is better to start from the front end of the cantilever and finally connect with the front concrete
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Cantilever construction site figure 21
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The bridge expansion device should be installed by post embedding method, that is, the bridge deck layer should be paved first, and then the reserved groove should be cut to install the expansion device
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22
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The bridge deck waterproof engineering should be divided into two waterproof grades according to the type of bridge, geographical location, natural environment, road grade and service life of waterproof layer
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23
.
When asphalt concrete pavement is used for urban bridge deck, flexible waterproof materials such as waterproof membrane or waterproof coating shall be used for waterproof layer
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When using cement concrete pavement surface, it is better to use cement-based permeable crystalline rigid waterproof, and it is strictly prohibited to use coiled material waterproof
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24
.
In the design of bridge deck waterproofing in urban bridge engineering, the composite use of waterproofing membrane and waterproofing coating is not suitable
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When the longitudinal or transverse slope of the bridge deck is greater than 4%, it is not suitable to use the membrane waterproof layer
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25
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When the radius of horizontal curve of bridge deck is less than or equal to 60m, waterproof coating should be used for bridge deck waterproofing
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For the bridge with waterproof grade I, the thickness of asphalt concrete surface layer above the membrane waterproof layer shall not be less than 80 mm.26 the waterproof system of bridge deck pavement in urban bridge engineering shall adopt different structural forms according to the deck pavement surface material, waterproof grade and natural conditions
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27
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For urban bridge engineering, the waterproof layer can be constructed only when the base concrete strength reaches more than 80% of the design strength
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The surface roughness of the base concrete should be treated by shot blasting
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The floating ash on the base surface should be removed, and there should be no sundries, oil materials, organic matter, etc
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28
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Before laying the waterproofing layer of urban bridge deck, the local treatment of nodes, corners, drainage outlets and other parts should be done well, and then large-area laying should be carried out
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29
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In the construction of waterproof coating for urban bridge deck, node treatment should be done first, and then large-area coating should be carried out
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Corners and facades shall be reinforced in detail according to the design requirements, without weakening, disconnection, flowing and accumulation
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30
.
The structural joints of cement concrete pavement and base concrete of urban bridge deck waterproof engineering shall be cleaned, and the embedded sealing materials shall be firmly bonded, sealed and waterproof, and the primer shall be used as required
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31
.
When the waterproofing material is coiled material and polyurethane coating, the moisture content of base concrete should be less than 4%
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When the waterproofing material is polymer modified asphalt coating and polymer cement coating, the moisture content of base concrete should be less than 10%
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32
.
The paving temperature of asphalt concrete on the bridge deck waterproof layer shall match the heat resistance of waterproof membrane
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The paving temperature of asphalt concrete on the membrane waterproof layer should be higher than the heat resistance of waterproof membrane, but at the same time, it should be less than 170 ℃; the paving temperature of asphalt concrete on the coating waterproof layer should be lower than the heat resistance of waterproof coating
.
33
.
The renovation of the top surface of highway subgrade should be carried out according to the specific situation of quality defects by adopting reasonable schemes and techniques
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The compacted thickness of the filling soil layer shall not be less than 100 mm
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After compaction, the surface shall be flat and free from looseness and peeling
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34
.
The highway subgrade test section should be selected in the section with representative geological conditions, section type and other engineering characteristics, and the length of the section should not be less than 100m
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35
.
The filling materials with different properties shall be filled in horizontal layers and sections and compacted in layers
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The same filling material shall be used for the full width of the subgrade in the same horizontal layer, and mixed filling is not allowed
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The continuous thickness of each filling layer after compaction should not be less than 500mm
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When filling the last layer on the top of roadbed, the compacted thickness shall not be less than 100 mm
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36
.
The compactness of Soil Subgrade of lower embankment with depth greater than 1.50M below the top surface of roadbed of Expressway and first-class highway shall not be less than 93%, that of second-class highway shall not be less than 92%, and that of third-class and fourth-class highway shall not be less than 90%.
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