Guangzhou Steel tells you: engineering professionals must know the 12 Building Knowledge
Summary: 2, Beams destruction - shear force factors: shear span ratio, high-span ratio, concrete strength; stirrups; the number of bent steel; the greatest impact stirrup rates. . C) seismic requirements have reinforced to increase E, meet: tensile strength than the measured value and the measured value of the yield strength of not less than 1.25, the yield strength of the measured value and the standard value is not more than 1.3, the maximum total elongation of not less than 9 %;
1 safety, serviceability, durability, reliability generalization become
1. Safety - bearing capacity limit state - control structure does not appear instability Collapse - strength requirements;
2, the structure of applicability - limit state - requirements to control the deformation amplitude, crack - stiffness requirements;
3, the deformation control element 4; load, span, material properties, cross sectional dimensions;
4, the durability of concrete structure requirements - minimum strength grade concrete, concrete structure is 50 years minimum concrete strength grade C25 in IA, IB, IC environment, C30, C35;
5, the minimum concrete cover thickness of steel: the minimum thickness of the protective layer of reinforced not be less than the diameter of longitudinal reinforcement; large section of the concrete pier is increasing under the premise of the protective layer thickness, concrete strength can be reduced up two, but can not less than C25 (100) and C20 (50 years), to reduce the strength of concrete level, the protective layer thickness increases 5mm, two concrete strength decreases, the protective layer thickness increases 10mm.
2 reliability assessment: safety, serviceability, durability, resistance to disasters assessment
1, structural reliability is the reliability of quantitative representation;
2, load factors, load value multiplied by coefficient greater than 1;
3, the material partial factor, divided by the resistance of the material is greater than the coefficient 1;
4, different security levels structural adjustment factor of safety.
3 bar stable concept four factors
1, the section is directly proportional to the length of material is proportional to the fulcrum fixed way; when both ends fixed 0.5L, one end fixed at one end hinged 0.7L, ends hinged 1L, Fixed End freedom 2L;
2, slenderness ratio coefficient is less than 1.
4 power balance calculation
Any object at equilibrium force, the object is at rest or in uniform motion, ΣX = 0, ΣY = 0, ΣM = 0; Analyzing moment diagram - depending on the structure by external forces, bending moments computing architecture FIG shear diagram; that moment when the concentrated load Pictured slash, shear Pictured straight; when that moment Pictured uniform load curve, shear Pictured slash.
5 seismic concept
1, against the larger earthquake tectonic earthquake, magnitude M> 5 earthquakes of destructive earthquakes; points and 12 intensity levels; meaning basic intensity, the probability of an earthquake in the region occurred more than basic intensity is 10%;
2, seismic three objectives: minor earthquake, the earthquake can repair, earthquake does not fall;
3, the stiffness of the structure greatly member force, the greater the stiffness of the more vulnerable places destroyed; the size of the force is proportional to the size of the earthquake and the building quality, good selection of high-strength lightweight materials seismic performance;
4, the seismic performance of reinforced concrete structural system: cylinder> Shear> Frame - Shear Wall> Frame; frame structure of the damage is greater than the bottom of the column capitals, columns and beams junction serious damage, corner posts damage greater than the general column short column damage greater than the general column; infilled and frame junction, column, beam ends 0.5M stirrups encryption;
5. masonry buildings earthquake resistant measures: a corner portion of the exterior wall junction and add structural column, the column structure 240 * 180, reinforcement 4 * Φ12, stirrups Φ6, horse teeth Croucher foundation ± 0 or less 500mm; b rigidity occurs. point mutations most likely to damage occurred in the floor and wall junction plus ring beam;. c strengthen the wall connection;. d to strengthen the integrity of the stairwell, stairway resting on each platform plus ring beam, stairwell corner portion plus structural column;. e beading wall pass with 2 ¢ 6 length along high spacing 0.5m.
6 roof covering system
Arched truss force smallest and most uniform; truss force's largest and most uneven; planar structure: truss, single suspension, arch structure; spatial structure: grid, cable net, shell structure; structural members only tension : cable structure; structural members only compression and shear forces: arch structure, shell structure; structural members as well as the existing tension compression: truss; grid.
7 Continuous Beam force characteristics
1, n-section failure - Moment - the most influential factor is the reinforcement ratio;
2, Beams destruction - shear force factors: shear span ratio, high-span ratio, concrete strength; stirrups; the number of bent steel; the greatest impact stirrup rates.
3, suitable for bars, small bars, super rib damage characteristics.
8-way bi-plate plate defined
1, the main beam calculated by elastic theory, secondary beams and plates can be considered a method of internal force redistribution of plastic deformation calculation;
2, the length of the edge is greater than or equal to 3-way slab, reinforced put the short side;
3, less than 3, two-way direction of the reinforced plates are placed, put the short side bars below;
4. Ministers independent column foundation reinforced bottom edge down side.
Claim 9 Guangzhou steel and structural steel engineering
1, steel structure requirements: design full penetration of twelve ultrasonic flaw detection, ultrasonic flaw detection can not be used with radiation detection;
2, welders must hold a certificate for employment; welds using paint, anti-corrosion after the first fire, when to stay in the weld corrosion coating 30-50mm do not weld inspection test;
3, steel connection: bolts, high strength bolts connecting a fixed order, carried from the site of stiffness to unfettered free ends early twist, re-tighten the final twist 24h complete; no design requirements, after first fastening bolt welding construction to corrosion then fire;
4, steel properties: Tensile properties: yield strength, tensile strength, elongation, impact resistance, brittleness critical temperature; fatigue properties - alternating load Holland repeated the role;.
5, HPB light round, HRB ribbed, HRB400 New Grade III national norms advocated the use of steel, validation approach:
. A) quality inspection documents (registration certificate manufacturer, factory test report issued appearances certificate);
b) on-site inspection (number of varieties appearance quality).;
. C) seismic requirements have reinforced to increase E, meet: tensile strength than the measured value and the measured value of the yield strength of not less than 1.25, the yield strength of the measured value and the standard value is not more than 1.3, the maximum total elongation of not less than 9 %;
. D) cold-drawn steel straightening elongation level of 4%, 1% of secondary steel;
6, fireproof performance is poor. When the temperature reaches 550 ℃, the yield strength of steel to the normal temperature yield strength of about 0.7;
7, carbon steel Q- yield strength, ABCD impurities from more to less, F boiling steel, Q235-AF; steel harmful elemental phosphorus - reduced ductility and toughness, sulfur - reducing mechanical properties, oxygen - lower ductility and toughness.
10 stairs: the width of the stair
Residential hospital 1.3m 1.1m, rest platforms - from the handrail to bend away from the wall, and greater than or equal to the width of the stair of not less than 1.2m, platform and platform height 2m, up and down stairs segment elevation 2.2m, stepping armrest height 0.9m, multi-storey residential railing not less than 1.05m, senior 1.10m; nursery 1.2m, vertical railings spaced not more than 0.11m, without spiral staircase for evacuation and spiral staircase, near the center of the staircase width 220mm; landings refractory not less than 1 hour bench of not less than 0.25 hours.
Detailed structure of the wall 11
Outside plinth site concrete and mortar or posted outside the stone waterproof durable material, the height of not less than 700mm, closed moisture protection system should be bulk water, the walls of the horizontal moisture barrier layer is formed; bulk water gradient of 3% -5%, bulk water width appropriate for the 0.6-1 meters, more general than the eaves 0.2-0.3 meters; interval 20m expansion joints; within Example northern housing insulation, exterior wall near the winter indoors appear damp ground, because inside the insulation to the floor at the break, cold bridge effect within close range of the external walls of 1m ground temperature below the dew point temperature, leading to condensation and damp.
12 fire doors, fire windows partition
ABC three, hour fire resistance of 1.2,0.9,0.6
Firewall open Class; evacuation stairwell door B; vertical tube wells inspection doors Class C; fire doors only swing open along the evacuation direction; more should be located in the floor on one side, should not cross Deformation; fire shutter fire resistance of not less than three hours, automatic sprinkler not less than 3 hours.
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