GB2476940A

GB2476940A - Crash barrier for use around edge of car park

Info

Publication number: GB2476940A
Application number: GB201000517A
Authority: GB
Inventors: David William Frederick Pope
Original assignee: BOURNE CONSTRUCTION ENGINEERING Ltd
Current assignee: BOURNE CONSTRUCTION ENGINEERING Ltd
Priority date: 2010-01-14
Filing date: 2010-01-14
Publication date: 2011-07-20
Also published as: GB201000517D0

Abstract

The barrier, for use as a vehicle restraint system around the edge of car parks, comprises structural rods 7 which are threaded 1 at each end and coupled together such that all of the rods can be pre-stressed by applying stress at one location along their length. The rods are supported by box support chassis 6 secured to the primary support structure 5 of the car park and during normal working conditions the pre-stress loads are distributed between the two end supports with no load being placed upon the intermediate supports. In the event of an impact, end caps 4 transfer impact forces to the support chassis adjacent the impact which in turn transfer load back to the structure. The system can be combined with a light weight mesh to fulfil a further safety function of being a pedestrian/child safety barrier.

Description

Boiu-ne Barrier

Background of Invention

This invention relates to a crash barrier / vehicle containment system.

The edge protection for car parks must fttlfill two primary safety functions; vehicle crash/restraint barrier, pedestrian/child safety barrier. The dimensions of barriers must comply with national standards.

In its capacity as a vehicle crash barrier, the edge protection must keep an errant vehicle within the structure. The design should be aimed at avoiding any large-scale damage and disproportionate collapse of the structure.

The requirements for containing the errant vehicle include the constraint that any impact does not dislodge the cladding onto pedestrians.

There are three principle types of crash barrier; those that span between primary structural members (commonly horizontally between the columns), those that cantilever up from the car park deck, and those that are monolithic with the deck.

Using structural rods as a method of vehicle contaimnent spanning between primaiy structural members has a number of difficulties. If a structural rod system were to he used without any manner of pre-stress force then the deflection of the system upon impact would be excessive. Pre-stressing structural rods at, or between, every structural support location adds complexity to the system, whilst also being difficult to control in terms of applied pre-stress forces. Pre-stressing structural rods at the end terminations only without intermediate tensioning points either increases the tension force required within the rods above acceptable limits, or limits the effective span of the system (i.e. the uninterrupted length between tensioning points) to modest lengths.

Statement of Invention

To overcome these problems, the present invention proposes a structural rod vehicle containment system which is pre stressed with a single rod tensioning point, which is continuous over intermediate supports, which limits the mohilised length of rod upon impact and which does not impose load upon intermediate structural supports under normal working conditions.

Advantages of Invention The present invention ensures that upon impact only the length of rod within the incident bay is mobilised due to the locking mechanism present at each structiu-al support location whilst also ensuring the reduced deflection benefit under impact of applied pre-stress to the system is not diminished.

The present invention can be used over extended lengths without the requirement for additional levels of pre-stress or the breaking of the system for the provision of extra pre-stress points. The system only requires a single tensioning location in its uninterrupted length.

Preferably the system ensures that deflections are kept within reasonable levels such that vehicular impact will not dislodge any cladding onto pedestrians.

Preferably the system is combined with a light weight mesh to fulfill the second safety fttnction of being a pedestrian/child safety barrier.

Pre-stress forces are preferably applied at the end terminations, although the pre-stress force may be applied by other means at alternative locations such as a tumbuckle within a structural bay.

Preferably the system can be constructed from numerous smaller elements connected together and does not rely on being manufactured from an unintemipted length of structural rod.

Introduc(wn to Drawings The invention will now be described solely by way of example and with reference to the accompanying drawings in which: Figiu-e 1 shows a perspective view of a typical restraint assembly fixed to an intermediate structural support point according to the invention; and Figure 2 shows a top elevation of a typical restraint assembly according to the invention; and Figure 3 shows a side elevation of a typical restraint assembly fixed to an intennediate structural support point according to the invention; and Figure 4 shows a long section passing through the outer box chassis of a typical restraint assembly according to the invention; and Figure 5 shows a long section passing through the entire construction of a typical restraint assembly according to the invention; and Figure 6 shows a long section perspective passing through the outer box chassis of a typical restraint assembly according to the invention; and Figiu-e 7 shows a short section perspective passing through the entire construction of a typical restraint assembly according to the invention; and Figiu-e 8 shows an exploded perspective view of a typical restraint assembly according to the invention; and Figiu-e 9 shows an exploded perspective view of a typical restraint assembly according to the invention indicating internal elements; and Figiu-e 10 shows a perspective view indicating a typical bay affangement according to the invention; and Figure 11 shows a perspective view indicating an alternative bay and rod affangement according to the invention.

Detail Description

Description of system with reference to drawings.

The following references, in accordance with the drawings provided, are used in the detail description.

1) Threaded part of rod 2) Structural rod nut 3) Washer 4) End cap 5) Structural support 6) Structural box chassis 7) Structural rod 8) Structural rod coupler 9) End cap location segment 10) Gap between structural rods at coupling location 11) Thread at coupling location 12) End connection 13) Mid span connection point A structiual rod (7) is threaded (1) at either end. On to the threaded part of the structiu-al rod a nut (2) is positioned. A washer (3) is added, followed by the end cap (4). This combination of parts forms the basic assembly. The basic assembly is passed in to the outer chassis (6) and attached to a similar assembly of parts via a coupler (8). End caps (4) are held in place via the hand tightened structtu-al rod nuts (2). Structural rod nuts should remain loose from the end caps until the required pre stress has been added to the system. End caps (4) are indicated with an end cap location segment (9). This enables the full assembly to be located conectly in relation to the box support chassis (6), and with that ensiu-e that upon impact the transfer of load via bearing in to the box support chassis is as expected.

There are a number of ways in which pre stress can be added to the system and the system is not reliant on any particular method. For example, pre stress may be added to the system by the tightening of the structural rod nut (2) located at either one of the end connections (12) with the use of a torque wrench. Pre stress can also be added to the system via a tumbuckle located within one of the structural rod bays (13).

For the affangement outlined; the structural box chassis (6) is required to have a permanent, rigid connection to an appropriate structural support system (5) which could typically be constructed from steel or concrete although this invention does not rely on any particular form of construction for the permanent support.

The extended length of threaded rod (1) facilitates easy installation of the system. The coupler (8) and rod system (comprising elements (1), (2), (3), (4), (7), (9)) are all able to be translated laterally in the direction of the structural rods.

Fixings between multiple hays of structural rods are able to he made externally to the outer box chassis (6); in turn meaning that erection merely requires the rotation of the counter threaded couplers (8) and does not necessitate the rotation of n-iultiple structural rods. Tolerance in structural rod length can be accommodated by the inclusion of a gap between the structural rods at the coupling location (10).

Where space at the ends of the system is limited (12), and does not permit the translation of the rods described above, couplers (8) between structural rods in the end bay can be threaded normally and the structural rods in the end hay rotated to make the connection. This ensures that there is never an issue with space during erection.

During normal working conditions any pre stress load within the system will be distributed between the two end supports and no load will be incident upon any intermediate supports. Upon vehicular impact, the increased axial forces resultant in the structural rods will be resisted by the structural support connections local to the impact defined in this description.

The affangement of the system described here limits the length of structural rod mobilised upon impact to the impact bay only.

It is not essential to the design that the structural box chassis (6) be completely enclosed and the form of this element will he material dependent. Figure 6 is indicative of the anangement for a non enclosed box chassis. Upon vehicular impact, a resultant axial force exists within the structural rods (7). This axial force is transmitted in to the end cap (4) via direct hearing from the structural rod nut (2) and the washer (3). The compressive load in the end cap is fttrther transmitted in to the outer box chassis (6) in bearing which in turn transmits this force hack to the primary structural supports.

Figure 11 illustrates a possihle arrangement of multiple rods.

Claims

Claims 1) A structural rod vehicle containment system which is pre stressed with a single rod tensioning point, which is continuous over intermediate supports, and which limits the length of rod mobilised upon impact.
2) A structural rod vehicle containment system according to claim 1, which does not impose resultant load due to pre stress upon intermediate structural supports under normal working conditions.
3) A structural rod vehicle containment system according to claim 2, which can be used over extended lengths.
4) A structural rod vehicle containment system according to claim 3, which can be replaced in sections.