Static Load Testing of Fibre Reinforced Precast Burial Vaults
Independent structural testing plays an important role in validating new precast concrete designs and optimising reinforcement systems. As part of an ongoing product development programme, American Wilbert Vaults Corporation commissioned Wiss, Janney, Elstner Associates, Inc. (WJE) to evaluate the structural performance of five precast burial vault designs incorporating BarChip macro synthetic fibre reinforcement.
Testing was undertaken in accordance with the Catholic Cemetery Interment Specification (CCIS) 210.6, which requires burial vaults to withstand a static compressive load of 5,000 lb applied over a one square foot area while remaining within strict deflection limits. The objective was not simply to determine whether the vaults passed or failed, but to optimise reinforcement and validate alternative precast designs through independent structural testing.
Independent Structural Testing
Testing was carried out at the WJE structural laboratory using a hydraulic loading frame that applied a controlled static load through a one square foot loading plate positioned at the centre of each vault lid. Load was applied in 500 lb increments, with vertical and lateral deflections continuously measured until structural failure occurred or testing was completed.
Five different reinforcement configurations were evaluated to understand the interaction between fibre reinforcement, conventional steel reinforcement and burial vault geometry.
| Vault | Reinforcement Configuration | Result |
|---|---|---|
| Vault 1 | Fibre reinforcement only (flat lid) | Did not satisfy CCIS requirements |
| Vault 2 | Fibre + 3 longitudinal reinforcing bars | Did not satisfy CCIS requirements |
| Vault 3 | Fibre + 3 longitudinal + 5 transverse reinforcing bars | Passed CCIS testing |
| Vault 4 | Fibre + 2 longitudinal reinforcing bars (vaulted lid) | Passed CCIS testing |
| Vault 5 | Fibre reinforcement only (vaulted lid) | Passed CCIS testing |
The results demonstrate that structural performance depends on both reinforcement design and the geometry of the precast element. Rather than simply increasing steel reinforcement, the testing enabled reinforcement to be optimised for each vault configuration.
Structural Performance
The independent testing produced several important engineering outcomes.
- Three of the five burial vault designs successfully met the CCIS 210.6 performance requirements.
- The fibre-only vaulted burial vault successfully exceeded the required 5,000 lb static load, demonstrating that carefully engineered fibre reinforced concrete can satisfy demanding structural performance requirements without conventional steel reinforcement.
- Vault geometry was shown to have a significant influence on structural behaviour, highlighting the importance of combining appropriate structural design with reinforcement optimisation.
- Throughout testing, vertical and lateral deflections remained well within the allowable specification limits for the vaults that successfully completed the programme.
Rather than focusing solely on ultimate load capacity, the testing programme evaluated cracking behaviour, deflection characteristics and failure mechanisms to better understand the structural behaviour of each reinforcement configuration. This information enabled American Wilbert to refine future burial vault designs using independent engineering data.
Load-deflection response of Vault 5 during CCIS 210.6 static load testing.
Engineering Through Testing
One of the most valuable outcomes of this programme was not simply demonstrating that a fibre reinforced burial vault could satisfy the specification, but showing how independent testing can be used to optimise reinforcement and validate new precast concrete products.
The WJE testing demonstrated that BarChip macro synthetic fibres can form part of an engineered reinforcement solution when combined with appropriate structural design and product testing. Rather than relying on conservative reinforcement assumptions, manufacturers can use independent testing to optimise performance, reduce reinforcement complexity and validate new precast concrete products before commercial production.
BarChip’s experienced engineering team can support your project with comparative analysis, structural design and, where appropriate, advanced finite element analysis (FEA). Design with BarChip and design with confidence.