a low impact solution for increasing existing structural loads
DESCRIPTION
Using a minimally invasive structural resin, Uretek Mid-Atlantic was able to increase the load bearing capacity of existing foundations for a factory expansion.TRANSCRIPT
A Low Impact Solution for Increasing Existing
Structural LoadsOriginally Presented by Bryan Honeycutt,
Technical Sales Manager
South Carolina & Charlotte
Edited & Designed by Katherine Witt,
Marketing Assistant
BackgroundA reputable automobile manufacturing plant in Greer, SC was in the process of expanding its facility. Plans called for the addition of a penthouse and an additional wing. Consequently, existing column foundations were subjected to significant load increases. The additional weight necessitated the increase of load bearing capacity for the existing foundations.
New Loads on Existing Columns
Increased loads required column modifications
Effects of New Loads on Foundations o Soil Bearing Pressure increase due to new vertical loads
applied at top of columns from penthouse addition.
o Soil Bearing Pressure increase due to new lateral loads applied at top of columns from penthouse addition; higher moments at bottom of columns and foundations.
o Soil Bearing Pressure increase due to increase in column stiffness.
Penthouse Expansion
Existing Penthouse
New Penthouse
o New Penthouse Structure Tying into Existing Penthouse Structure
o 50’x50’x23.75’ Bayo Roof trusses and floor framing
above existing roof; column extensions
o Replacing Equipment in Existing Penthouse Structure
o Replacement of existing foundation
o Conventional foundation modification / enlargement
o Installation of New Columns to reduce loads on Existing Columns
o Micropiles o Subgrade modification
OptionsThere were several viable options to increase the load bearing capacity of the foundations.
Considerations
o Costo Invasiveness o Impact on factory productiono Associated time relative to fast track
schedule
Conventional options were relatively expensive and time consuming.Uretek Mid-Atlantic was contacted to investigate an alternative solution. After reviewing the proposed structural design criteria and geotechnical data regarding existing subgrade capacities, Uretek determined that subgrade enhancement would be an overall better solution.
Uretek designed and implemented a solution to increase the capacity of existing structural foundation support soils utilizing their patented High Density Polyurethane Resin and Deep Injection™system.
An Innovative Alternative
High Density Polyurethane Resin(HDPR)
o Hydrophilic, Hydrophobic and Hydroinsensitive* (URETEK 486 Star)
o Two Component Polymerization Process o Injected as a liquid, chemical reaction expands and changes
the liquid into a solid
*“Hydroinsensitive”, meaning it will react in a saturated environment as it does in dry conditions; traditional polyurethanes require some degree of moisture to react properly
Benefits of Using HDPRo Increased Properties of Unconsolidated Soils
o Increases bearing capacity by increasing density or internal angle of friction or both
o High Expansive Forces o High lifting capacity to weight of material ratio o Addresses Inflow and Infiltration (I&I)
o Seals underground structures
Benefits of Using HDPR, cont…
o Minimal Disruption: No Digging Develops 90%
Strength in 15 minutes Fully cured in 24 hours
o Return to service in 1 hour
o Excellent Chemical Resistance
o Long Term Structural and Dimensional Stability
o Environmentally Benign
Product Testing
HDPR injection to soil.
Congealed HDPR and soil after application.
Deep Injection
Minimally invasive injection ports.
Deep Injection
Injecting material while monitoring the structure to avoid any undesired movement.