What factors influence the installation height of bollards?

The installation height of bollards (the height of the bollard above ground) is affected by multiple factors and requires comprehensive design considerations based on functional needs, safety standards, and site characteristics. Key influencing factors and their explanations are as follows:

I. Protection Target and Collision Resistance Level

1. Type of Object to be Blocked

Ordinary vehicles (cars, SUVs): Should be higher than the vehicle's undercarriage height (15-20cm), usually set to 40-60cm, to prevent scraping while restricting accidental entry.

Large vehicles (trucks, lorries): Should exceed the vehicle's bumper height (40-50cm). In high-security scenarios, it should reach 60-100cm, combined with high-strength materials (such as stainless steel + internal steel structure) to withstand collisions.

Anti-terrorism needs: Must comply with international collision resistance standards (such as the US ASTM F2656). The height must match the vehicle's weight and impact speed. For example:

When blocking a 7.5-ton truck (80km/h), the height must be ≥100cm, the bottom diameter ≥50cm, and the buried depth ≥200cm.

2. Industry Safety Regulations

Government and financial institutions need to follow the requirements of the relevant anti-terrorism laws, and the bollard height must pass professional collision resistance tests (such as dynamic impact tests).

Transportation hubs, border checkpoints, etc., must comply with the "Highway Traffic Safety Facility Design Specifications", and the height must meet the requirements for rapid interception (such as 80-120cm).

II. Usage Scenarios and Traffic Needs

1. Scene Functional Positioning

2. Traffic Efficiency and Emergency Situations

Areas with mixed pedestrian and vehicle traffic: Height ≤50cm, to avoid affecting wheelchairs and strollers, needs dense arrangement (spacing ≤1.5 meters).

Emergency evacuation passages: Bollards that can be linked to the fire system should be set up. The recommended height is below 60cm to ensure unimpeded passage for ambulances and fire trucks (approximately 20-30cm undercarriage).

III. Ground Environment and Installation Conditions

1. Terrain and Slope

In sloped scenarios (slope >5°), the effective height should be calculated from the lowest point of the bollard base. For example: If the slope height difference is 20cm, and the target effective height is 60cm, the bollard at the high point needs to be installed to 80cm, and the bollard at the low point to 60cm, ensuring consistent blocking effect on both sides.

In low-lying areas (such as underground garage entrances), drainage needs to be considered, and the bollard height needs to allow for the impact of floods or accumulated water (such as more than 50cm above the ground to avoid soaking the motor).

2. Underground Pipelines and Foundation Construction

If there are cables or water pipes underground, the buried depth needs to be adjusted (usually the underground buried depth is 1.5-2 times the above-ground height). If the buried depth is limited (such as ≤50cm), the above-ground height should be ≤30cm, and only suitable for light isolation (such as sidewalks).

The thickness of the concrete foundation must match the height: For a 60cm bollard, the foundation thickness ≥30cm; for a 100cm anti-collision bollard, the foundation needs ≥50cm and reinforcement.

IV. Regulations and Supporting Facilities

1. Urban Planning and Traffic Regulations

Installation on city roads must comply with the "Urban Road Engineering Design Specifications"; the height of obstacles must not exceed the road height limit (if there are no special regulations, the general road height limit is 4.5 meters, but bollards are local obstacles and need to be reported separately).

Installation in residential areas and commercial areas requires planning approval; the height must not affect the lighting or traffic sightlines of adjacent buildings (such as within 20 meters of an intersection, height ≤30cm).

2. Signage and Interlocking Equipment

Bollards with a height >50cm need to be equipped with reflective markings and warning lights (brightness ≥150cd/m²) to avoid collisions at night.

When linked with license plate recognition and access control systems, the height must be lower than the camera installation height (usually 1.5-2 meters) to ensure clear license plate recognition.

V. Cost and Maintenance Needs

1. Equipment Type and Budget

Hydraulic bollards: The higher the height (such as 100cm), the larger the power motor and thicker oil cylinder required, increasing the cost by approximately 30%-50%.

Electric bollards: The cost-effectiveness is highest when the height is ≤60cm. Exceeding this range requires structural reinforcement, increasing maintenance costs (such as faster wear and tear of seals).

2. Long-term Maintenance Convenience

High-height bollards (>80cm) need regular checks of the bollard's verticality (deviation ≤2°) to avoid tilting due to foundation settlement; buried bollards need to reserve inspection wells, with a depth consistent with the buried depth (such as 100cm above ground, 200cm deep inspection well).

VI. Special Functional Requirements

1. Adjustable Height Design

Some scenarios require multiple height settings (e.g., 30cm temporary isolation, 60cm standard barrier, 100cm anti-terrorism mode). Products with programmable controllers should be selected for remote or local button switching.

2. Landscape and Aesthetic Requirements

In scenic areas and historical districts, the height of the bollards should be coordinated with the surrounding architectural style (e.g., the height of antique stone pillars is 40-60cm), and carvings and paintings can be customized.

Summary: Design Process Suggestions

Clarify core needs: Prioritize determining "what vehicles to block", "whether crash testing is required", and "emergency passage requirements".

On-site survey: Measure ground slope, underground pipelines, and surrounding obstacles (e.g., streetlights, building steps).

Regulatory compliance: Consult local transportation and planning departments for restrictions to avoid illegal installation.

Supplier collaboration: Provide scene parameters (e.g., traffic flow, vehicle type), and refer to the manufacturer's "height - impact resistance - cost" table to select the optimal solution.