ATS Advanced Turf – Design guidance for vehicle access routes

The Advanced Turf System (ATS) is suitable for a wide range of trafficked applications where a free-draining, compaction resistant and high load bearing, discreetly reinforced natural grass surface is required. Typical applications include fire & emergency access lanes, HGV maintenance & MEWP routes, overflow parking, event areas, helipads & airfield aprons, pedestrian & disabled access and sculptured slopes.

This document is intended to be a summary presenting typical solutions. Contact ABG for site specific advice.

Typical construction detail:

ATS Advanced Turf - Design guidance for vehicle access routes

Notes:

a. For advice on the installation and maintenance of ATS, please refer to the ABG Advanced Turf® Installation Guide.

b. Advice on subgrade CBR% strengths, ground conditions, and construction over weak ground is available from ABG.

c. Alternative ABG stabilisation geosynthetics may be used in lieu of ABG Abgrid geogrid. These include ABG Gridtex Type 2 high strength woven geotextile or ABG Abweb geocells. If the subbase stabilisation is omitted, the total subbase layer thickness (‘D’ on Table 1) is typically increased by a minimum of 50%.

D. Subbase design options:

d1. Where a porous subbase is required for SuDS applications a permeable open-graded (reduced-fines) aggregate is recommended, such as DTp Type 3 low-fines roading aggregate, or BS 7533-13:2009 SuDS aggregate (4/20 or 4/40).

d2. Where a non-porous subbase is required a conventional DTp Type 1 subbase is recommended. It is essential that a drainage system such as ABG Fildrain is incorporated. Specific advice is available from ABG.

d3. Where no subbase layer is required (such as on subgrade soils with a CBR > 6%), the geotextiles and subbase stabilisation can be omitted.

e. Maximum subbase particle size should match minimum subbase thickness but must not exceed 75mm diameter. For subbase thicknesses of around 100mm, a minimum 37.5mm particle size should be adopted to allow effective installation of the Abgrid.

f. The subbase must be overlaid by a Terrex NW9 geotextile to provide separation, enhanced water treatment function and prevent migration of the bedding layer.

g. Typical paving edge restraint solutions include concrete, timber, railway sleepers, steel, heavy-duty plastic, or by simply leaving a 45° battered edge to the compacted ATS rootzone layer where it will abut an adjacent grassed area.

h. Advanced Turf Access Routes can be delineated using kerbs, bollards, marker posts, trees or planted areas as required.

i. Fertiliser will help to establish and maintain a healthy grass sward which is capable of sustaining traffic. Local and seasonal weather conditions will determine the degree of irrigation required. Inadequate irrigation during the grass establishment period may result in drought conditions and a failure to establish uniform quality grass cover.

j. The maximum advised gradient for fire access, disabled access, and other vehicular applications is 8% (1:12) 5°.

k. When designed in accordance with the recommendations, Advanced Turf complies with BS8300:2009 : “Design of buildings and their approaches to meet the needs of disabled people” – Code of Practice (ISBN 9780 580 57419) & Building Regulations Document ‘M’ Section 6.

l. All stated dimensions & weights are nominal and in accordance with manufacturing +/- tolerances.

m. The recommendations in this document are only suitable for use with ABG products.

n. Advanced Turf® is a registered trademark of Schweitzer-Mauduit International (SWM)

Table 1: Advanced Turf® System (ATS) typical DTp Type 3 subbase thickness (D) requirements – refer to specific construction drawing

Table 2: Field guidance for estimating subgrade shear strengths