Building structure retrofitting including integral reinforcement and member reinforcement, usually a component or a region needs to be strengthened, but the consolidation scheme should be considered from the overall structure, such as reinforcement beam should be considered when the pillars shall be strengthened, but also to consider whether foundation and base should be reinforcement. A lot of methods of building structure reinforcement, including improving bearing capacity, increase the stiffness method and crack control method, comparative analysis, design personnel should applicability according to the structural characteristics and strengthening methods of multi program, select the optimal method to achieve reliable technology, reasonable economy, convenient construction.

1 integral reinforcement

The overall reinforcement of the building is to strengthen the integrity of the structure, improve the structural damage form, and improve the lateral stiffness and seismic capacity of the structure. The common way is to add reinforced concrete aseismic wall or masonry wall in the building, or to make the non closed wall form a close strength by adding a new wall. 

When the brick or masonry structure beam, constructional columns do not meet the current design specifications, or the vertical and horizontal wall junction bite rub have obvious shortcomings, or the overall poor, should be added in beam and column of reinforcement. 

In the steel structure or in the industrial building and roof system to add horizontal support, inter column support and so on. The steel structure reinforcement method and change the structure of computational graphics, refers to the use of changing the load distribution, load transfer path, node properties and boundary conditions, additional and braces, prestressed reinforcement method of structure considering coordination work space; additional support structure stiffness increases, or adjust the structure self vibration frequency to improve the structural dynamic characteristics of bearing force and improve the structure; additional support or auxiliary rod structure of the slenderness ratio decreased to improve its stability; in bent structure strengthen a colonnade stiffness; in the tower structure setting rod or moderate tension cable to strengthen structure stiffness.

2 Member reinforcement

There are many ways to reinforce the building components.

2.2.1 enlarging the cross section method. By adding polymer mortar reinforced concrete, steel strand, steel member section area increase the punishment, improve the structure of bearing capacity and stiffness. It is suitable for reinforced concrete beams, plates, columns and walls, masonry columns and walls, and steel structural members.

2.2.2 bonding steel plate reinforcement method. The steel is outsourced around the force of the component to improve the bearing capacity of the structure. It is suitable for reinforced concrete beams, columns and masonry columns.

2.2.3 bonding carbon fiber composite reinforcement method. The load-bearing surface of the component is bonded with carbon fiber, glass fiber, aramid fiber, nylon fiber and so on, so as to improve the bearing capacity of the structure. Suitable for reinforced concrete beams and slabs, beams, columns; column; masonry wall.

2.2.4 steel mesh cement mortar surface layer method. The surface of the masonry wall is added as a steel mesh cement mortar layer to improve the aseismic ability of the wall.

2.2.5 reinforced concrete sandwich wall reinforcement method. The concrete wall or masonry wall is added to the surface of reinforced concrete to improve the seismic capacity of the wall.

2.2.6 winding reinforcement method. Lead wire, steel wire, carbon fiber or fiber resin winding round or square concrete or wood cracking component, improve the bearing capacity and ductility.

2.2.7 external prestressing reinforcement method. The strength and deformation ability of components such as bending, shearing and compression are improved by applying prestressed reinforcement to high strength steel or type steel, and the stress characteristics are changed. It is suitable for concrete beams, plates and columns; steel beams and columns.

For the wood, timber, timber and wood truss, according to the specific circumstances to adopt steel splint method, steel rod method and local underpinning method etc..