1 General Provisions
1.0.1 This Specification is formulated with a view to realizing the state-of-the-art technology, economy and rationality, safety and usability, and good quality during the design, construction and quality acceptance of high strength bolt connections of steel structures.
1.0.2 This Specification is applicable to the design, construction and quality acceptance of high strength bolt connections in the building steel structure engineering.
1.0.3 During the design, construction and quality acceptance of high strength bolt connections, not only the requirements stipulated in this Specification, but also those in the current relevant ones of the nation shall be complied with.
2 Terms and Symbols
2.1 Terms
2.1.1 Heavy-hex high strength bolt assembly
It refers to the assembly of connecting fastener composed of one heavy-hex high strength bolt, one heavy-hex high strength nut and two high strength plain steel washers.
2.1.2 Twist-off-type high strength bolt assembly
It refers to the assembly of connecting fastener composed of one twist-off-type high strength bolt, one heavy-hex high strength nut and one high strength plain steel washer.
2.1.3 Faying surface
It refers to the contact surface between high strength bolt connection slabs.
2.1.4 Pretension
It refers to the tension produced along bolt shank axis direction by tightening high strength bolt assembly and required to meet the connection design.
2.1.5 Friction-type joint
It refers to the connecting mode generating frictional resistance among connected pieces by high strength bolts tightening to transfer shear force and integrate components, units or plates.
2.1.6 Bearing-type joint
It refers to the connecting mode adopting screw rod shear and hole wall pressure bearing to transfer shear force and integrate components, units or plates.
2.1.7 Prying action
It refers to the additional pressure generated at the edge of connecting pieces due to connecting piece deformation and joint lever action caused by tensile load and bolt shaft axis deviation in the T-type tension joints.
2.1.8 Mean slip coefficient
It refers to the ratio of external slip force to normal pressure (identical to the bolt pretension) in connection during the slip of faying surface of high strength bolt connections.
2.1.9 Torque-pretension coefficient
It refers to the scale coefficient between the tightening torque applied on the nut and lead-in axial pretension (tightening axial force) on the bolt in the high strength bolt connections.
2.1.10 Connection of sharing on a shear load by bolts and welds
It refers to the joint type designed considering that friction-type high strength bolt connections and fillet weld share the same shear force.
2.1.11 Joint with combined bolts and welds
It refers to the joint type that flange adopts penetration weld connection and web adopts friction-type high strength bolt connection in the splice nodes of beam, column and supporting components as well as mutual connecting nodes.
2.1.12 Calibrated wrench method
It refers to the tightening method for high strength bolt assembly by controlling the construction torque values.
2.1.13 Turn-of-nut method
It refers to the tightening method for high strength bolt assembly by controlling the relative corner values of bolt and nut.
2.2 Symbols
2.2.1 Action and action effect
F--Concentrated load;
M--Bending moment;
N--Concentric force;
P--Pretension of high strength bolt;
Q--Prying force;
V--Shear force.
2.2.2 Calculation indices
f--Design values of tensile, compression and bending strength of steels;
--Design value of bearing strength of high strength bolt connecting piece;
--Design value of tensile strength of high strength bolt;
fv--Design value of shear strength of steel;
--Design value of shear strength of high strength bolt;
--Design value of compression bearing capacity of single high strength bolt;
--Design value of tensile bearing capacity of single high strength bolt;
--Design value of shear bearing capacity of single high strength bolt;
σ--Normal stress;
τ--Shear stress.
2.2.3 Geometric parameters
A--Gross sectional area;
Aeff--Effective sectional area at the thread of high strength bolts;
Af--Gross sectional area of single flange;
An--Net sectional area;
Aw--Gross sectional area of web;
a--Spacing;
d--Diameter;
d0--Aperture;
e--Eccentricity;
h--Section height;
hf--Dimension of fillet weld leg;
