What lifting devices are used for Trenwa trench bases and lids?

Trenwa uses three types of lifting inserts depending on product type: coil inserts (require spreader beam for vertical pull), recessed anchors, and optional swift lift inserts (require special lifting tool, available at extra cost). BM and LM products use coil inserts. BH bases and LHC lids use coil inserts with optional recessed anchors or swift lifts. Fibrelite lids (LPF, LMF, LHF) use the FL7 lifting tool. LHC road crossing concrete lids use EB 3/4 coil eye bolts with cable slings at a 60-degree angle. A Crosby 320N hook rated 1.5–5 tons is specified depending on product weight.

How deep should the excavation sub-grade be for Trenwa trench installation?

For one-piece trench systems, excavate to a sub-grade elevation 4–6 inches below the bottom of the trench. If a drain tile is placed under the trench, increase this to 8–12 inches. For component trench systems, excavate to 2–3 inches below trench bottom (8–12 inches with drain tile). Trenwa recommends drain tiles to remove water and prevent washout of the sub-base.

What base preparation is required under a Trenwa precast trench?

After drain tile installation (if applicable), place Dense Graded Aggregate and compact with a vibratory plate compactor to bottom-of-trench elevation. The stabilized base should extend 4–6 inches wider than the trench to prevent washout. Top off with 1/4–1/2 inch of sand raked smooth for a uniform bearing surface for the trench base.

What sealant is recommended for joints between Trenwa trench bases?

Trenwa recommends standard elastomeric concrete adhesive applied to the end of each trench base before setting the next unit. This provides a bond and silt seal at joints. Roofing paper or geofabric may be placed over vertical joints as an alternative. For water-resistant joint installations, an exterior joint sealant material overlapping the joint is applied per the project drawings.

Can Trenwa trench bases be field modified to fit a layout?

If field modification appears necessary to match the trench layout, contact Trenwa directly to discuss options. In many cases it is preferable to have Trenwa fabricate a new trench base (and lid if required) rather than attempt field modification.

What are the concrete material specifications for Trenwa precast trench systems?

Trenwa precast concrete trench systems meet the following material specifications: minimum compressive strength of 5,000 psi at 28 days; 6% entrained air by volume (±1%); Portland cement per ASTM C150/C150M; aggregates per ASTM C33/C33M; chemical admixtures per ASTM C260/C260M and C494/C494M; steel reinforcing bars per ASTM A615; steel reinforcing wire per ASTM A496; welded wire mats per ASTM A1064; embedded steel shapes per ASTM A36. Design conforms to ASTM C857-19, ASTM C858-07, and ACI-318.

What are the interior dimensions available for Trenwa one-piece road crossing trench bases?

Trenwa one-piece road crossing trench bases are available in interior widths of 10, 20, 24, 30, 36, 40, 48, 60, 72, 84, and 96 inches, and interior depths of 12, 16, 24, 36, 48, 60, and 72 inches. All road crossing sections are designed to carry HS20 (32,000 lb axle load) and are furnished in standard 10-foot lengths with special lengths available as required by layout.

Do Trenwa precast trench systems require cross braces during installation?

No. Trenwa precast trench systems are designed and constructed so that neither covers nor temporary side-to-side braces are needed during installation, machine backfilling, or tamping. For road crossing trench, supplemental support such as protection rods or cross supports are not required.

How should Trenwa trench lids be handled to prevent damage during construction?

Keep trench lid surfaces and joints free of gravel and hard debris — vehicles forcing debris into joints can cause concrete to chip or spall. Pedestrian lids are designed for foot traffic only and must not have tool carts or wheelbarrows rolled over them. If pedestrian lids are removed, do not drop them on hard surfaces and stack no more than 10 high. Avoid use of salt-based deicers near concrete lids as they accelerate rusting of impact channels and damage concrete surfaces.

What is the procedure for installing LHC road crossing concrete lids?

Clean the lid bearing surface, then apply the continuous neoprene gasket pad (adhesive side down) to the full length of the bearing surface on each side of the trench base. Remove CP1 coil protectors using the CPT coil removal tool (use WD-40 if stuck). Install EB 3/4 coil eye bolts so the shoulder is flush with the lid top and the eye bolt is parallel to the lid length. Use cable slings maintaining a 60-degree angle at the hook point. Apply initial tension to check security before lifting. After setting lids, reinstall CP1 protectors with automotive grease on threads for future removal. Do not push or pull lids into final position — this damages the neoprene pad.