Overview
Cementitious structural bearings are prefabricated components designed to transfer loads between structural elements while accommodating movements caused by thermal changes, creep, or seismic activity. Unlike elastomeric bearings, they utilize cement-based materials reinforced with additives for enhanced performance. Their development emerged in the late 20th century as a fire-resistant and economical alternative to traditional bearing systems. These bearings are particularly favored in infrastructure projects where fire safety is critical, such as tunnels and high-rise buildings. The composition typically includes Portland cement, silica fume, and sometimes polymer modifiers, achieving compressive strengths exceeding 50 MPa. Their rigid yet slightly flexible nature makes them suitable for both static and dynamic load conditions.
Structure and Working Principle
A typical cementitious bearing consists of multiple layers: a high-strength cementitious core, steel reinforcement plates (if required for tensile strength), and sometimes sliding surfaces made of PTFE for movement accommodation. The core material is engineered to withstand high compressive stresses while allowing minor rotations and displacements. When installed between a bridge girder and pier, for example, the bearing distributes concentrated loads evenly across the substructure. Its slight flexibility absorbs vibrations from traffic or wind, reducing fatigue on the overall structure. Movement capability depends on design; some models incorporate sliding interfaces or elastomeric layers for greater displacement capacity, though pure cementitious types generally offer limited movement compared to rubber bearings.
Key Features
Fire resistance is a standout feature, with cementitious bearings maintaining integrity at temperatures exceeding 1000°C, unlike elastomeric types that degrade at 300°C. This makes them indispensable in tunnels and fire-sensitive applications. Their inorganic composition also resists UV radiation and ozone, ensuring long-term durability outdoors. Cost-effectiveness arises from locally available materials and simpler manufacturing compared to steel-reinforced elastomeric bearings. Customization is straightforward—thickness and reinforcement can be adjusted to meet specific load requirements (commonly 500 kN to 10,000 kN). However, their weight is higher than polymer alternatives, requiring consideration during transportation and installation.
Application Areas
Bridge construction accounts for over 60% of cementitious bearing usage, especially in short-to-medium span bridges where movement demands are moderate. They’re also specified in building columns to isolate vibrations from machinery or seismic activity. Industrial facilities, such as power plants, use them under heavy equipment due to their stability and fire safety. In retrofitting projects, these bearings replace deteriorated steel or rubber units with minimal structural modifications. Recent innovations include fiber-reinforced versions for higher tensile capacity and hybrid designs combining cementitious and elastomeric layers to balance fire safety with movement capability.
Maintenance and Precautions
Cementitious bearings require minimal maintenance but should be inspected annually for cracks or spalling, particularly in freeze-thaw climates. Surface sealing with waterproof coatings can prevent moisture ingress, which may cause frost damage or steel corrosion in reinforced models. During installation, ensure the bearing surface is level and clean to avoid point loading. Use non-shrink grout for bedding to prevent voids. In seismic zones, verify that the bearing’s movement capacity aligns with expected displacements. Avoid exposure to sulfates or chlorides unless specially formulated for such environments.
B2B Procurement Guide
When sourcing cementitious bearings, prioritize manufacturers with ISO 9001 certification and a track record in infrastructure projects. Request third-party test reports for compressive strength, creep behavior, and fire resistance (e.g., EN 1363-1). Lead times vary from 4-12 weeks depending on customization. Bulk orders (50+ units) may attract discounts of 10-20%. Consider total cost of ownership—while initial prices are lower than elastomeric bearings, logistics costs might offset savings due to weight. For export, verify compliance with destination-country standards; EU projects often require CE marking per EN 1337-10. Sample testing is recommended before large-scale procurement.
Related Manufacturers
- 主营：灌浆料、压浆料、高强无收缩灌浆料、水泥自流平、水泥路面修补料、支座灌浆料、自流平水泥、高延性混凝土、聚合物砂浆、石膏基自流平、路面修补料、预应力孔道压浆料、套筒灌浆料、轻质抹灰石膏、金刚砂耐磨料、道路修补砂浆、座浆料、注浆料、自密实混凝土、聚合物抗裂砂浆
- 主营：路面快速修补料、环氧胶泥修补砂浆、高强无收缩灌浆料、水泥自流平、抢修料
- 主营：丙乳砂浆、环氧树脂砂浆、混凝土增强剂、水泥基灌浆料、各种型号灌浆料、加固维修材料、玄武岩纤维砂浆、玄武岩纤维韧性砂浆、超高性能混凝土、高强聚合物砂浆、环氧混凝土
- 主营：灌浆料、压浆料、压浆剂、水泥基自流平灌浆料、注浆料、聚合物砂浆、高强修补砂浆、防水砂浆、抗裂砂浆、地面修补料
- 主营：环氧胶泥、环氧树脂砂浆、灌浆料、支座砂浆、水泥混凝土修补料、水泥地面修补施工、支座灌浆料、道钉锚固剂、聚合物修补砂浆、灌浆树脂、粘钢胶、植筋胶、混凝土界面剂、混凝土表面增强剂、重力砂浆、高强聚合物砂浆、环氧树脂灌缝胶、碳纤维布、环氧修补砂浆、道路修补料、聚合物加固砂浆、混凝土路面修补施工、起砂处理剂、碳纤维浸渍胶、清水混凝土保护剂
- 主营：灌浆料、环氧砂浆、聚合物砂浆、水泥路面修补料、结构胶、聚合物防水砂浆、压浆料、高强修补砂浆、压浆剂、砌筑砂浆、抗裂砂浆、抹灰砂浆、植筋胶、注射式植筋胶、高延性混凝土
- 主营：高强无收缩灌浆料、压浆料、聚合物砂浆、水泥地面修补料、结构胶、高强修补砂浆、防水砂浆、轨道胶泥、自密实混凝土、植筋胶、粘钢胶、碳布胶、环氧砂浆、高延性混凝土
- 主营：高强无收缩灌浆料、预应力孔道压浆料、高延性混凝土、水泥路面修补料、自密实混凝土、聚合物砂浆、环氧砂浆、轨道胶泥、植筋胶、粘钢胶、碳布胶、灌注粘钢胶、注射植筋胶、灌缝胶、抗裂砂浆、砌筑砂浆、环氧灌浆料
- 主营：灌浆料、植筋胶、加固材料、水泥自流平、重力砂浆、修补砂浆、高延性混凝土、高延 性混凝土、环氧砂浆、环氧树脂灌浆料
- 主营：不发火防静电耐磨地面、不发火防静电砂浆、不发火细石混凝土、设备支座灌浆料、nfj 金属骨料
- 主营：膨胀压浆剂、高强灌浆料、混凝土膨胀剂、支座灌浆料、无收缩灌浆料、灌浆料、膨胀剂、压浆料、聚合物砂浆、修补砂浆、压浆剂
- 主营：高强无收缩灌浆料、环氧胶泥、道路快速修补料、聚合物改性水泥砂浆、水泥基渗透结晶、水泥自流平、混凝土防碳化涂料、环氧树脂砂浆、聚合物防水砂浆、丙乳砂浆、环氧粘钢胶、环氧植筋胶、环氧碳布胶、裂缝修补胶、界面剂、108胶粉、环氧界面胶、封缝胶、环氧树脂注浆液