Methodology and Tools for Design/Assessment/Analysis Studies

Designing blast-resistant structures requires the use of methodologies that are substantially different than those normally used in conventional structural design. In fact, there is a whole host of specialty design tools and methodologies available for this type of work; moreover, K&C has developed or substantially enhanced several of these specialty procedures. Unfortunately, many of these tools are hard to get, are not well documented, can easily be misused, and embody procedures that are likely to be unfamiliar to the general design practitioner.

Engineering Tools

K&C has extensive experience developing software tools for generating blast-resistant designs as well as creating new or improved design methodologies. Many forms of blast effects tools are regularly used by the K&C staff in developing designs to enhance protection at a facility. This makes developing new and effective design tools of special interest to us and likely results in a better software package than one generated by someone not actually using these tools in their own design work.

Blast-resistant designs could not be effectively accomplished without the results from such models; for example, the design of blast-resistant reinforced concrete columns and the retrofit of existing columns to enhance their blast resistance. Our software packages provide a capability essential to the practitioner. Some of the design tools generated by K&C are described below.

Design Tool CBARD, Design of Blast Resistant Reinforced Concrete Columns

This software tool, (CBARD) Column Blast Analysis and Retrofit Design, runs within a few seconds on a PC. CBARD uses an SDOF model to compute the column's response to specific blast loads. This code allows the user to quickly pick column sizes, shapes, choice of rebar, and spacing. With that information the code determines the capacity of the column to resist a blast load. Some screen captures from the code are shown below that illustrate the use of closer spacing of ties to change the blast response from a brittle shear failure to a highly ductile flexure response.

Reinforced Concrete Column Example

Reinforced Concrete Column Example

Parking structure column's response to blast
Example Problem: Improve Blast Resistance of Rectangular Column
Column Size: 525 mm x 1,000 mm x 3,000 mm
Concrete: 60 Mpa
Charge: 250 kg TNT

Resistance of the column too low, add more ties to prevent shear failure.

Resistance of the column after addition of more ties: shear failure is prevented and column deforms under a blast load.

Blast Pro Building Assessment Code

This code uses a PI-curve approach to rapidly assess the response of an entire building to a blast load. This code also plots the blast load over the entire exterior skin of the building as a function of bomb location as well as uses a color code to indicate damage to the building's various components. The code also can construct an envelope of the vulnerability presented by a variety of threats.

BARDC Blast Barrier Design Code

A blast barrier can often give a structure protection and decrease the vulnerability of an attack.  This code allows us to compute the reduction of airblast as a result of the installation of a blast barrier as a function of the barriers design properties. This allows for the height and location of the barrier to be assessed in terms of the reduction in loading achieved for a facility behind it.

Curtain Wall Assessment Code

A curtain walls response to a blast load can be generated with this code. This is accomplished by BEA_CW in a manner that is highly efficient and allows the many complex details of a curtain wall and its response to blast to be modeled effectively. BEA_CW provides an easily used GUI for the use to specify the properties of the curtain wall.  This information is automatically handled off to LS-DYNA to perform the actual response calculation which returns the generated results to BEA_CW for post processing.

LS-DYNA, FEFLO, CTH, DYNA3D, and other Physics-Based Tools

K&C has developed several physics-based analysis tools and has extensive experience and expertise in running these types of tools

Services Include

• Blast resistant design.
• Guidelines and tools for design and analysis.
• Blast effects studies of new buildings.
• Comparative analysis of the effects of different design parameters on the blast resistance of members.