### Abstract

The stiffness probe method (SPM) is a new numerical procedure that calculates buckling loads. SPM probes the local stiffness of a given structure at the point of application of a small transverse perturbation force as the applied load is increased. The local stiffness degrades from a maximum for an unloaded structure to zero at the buckling load. An artifice spring is added to the original structure that eventually absorbs the full perturbation force at a prescribed small deflection, thereby keeping structural deformations small as the buckling load is approached. As a result, using an indicator that approaches zero at buckling rather than having to rely on increasingly larger deflections at buckling as in conventional P-Δ methods, SPM ensures an accurate numerical result for the critical load. We use SPM herein to study the behavior of one and two cross-arm cable-stayed columns under applied load. A formula is given to calculate the minimum slenderness that justifies converting a tube into a cable-stayed column. Various factors such as cable prestrain, cable cross-sectional areas, and tiers of cross-arms affecting column strength are examined for a series of cable-stayed columns. We find that cable-stayed columns may buckle either in a one-lobe symmetrical mode or two-lobe anti-symmetrical mode, the latter case being contrary to conventional thinking. A design example for a given cable-stayed column using the AISC Specification is presented. The effect of optimum cable prestrain to enhance column buckling strengths is discussed. A strength enhancement ratio (SER) is defined that evaluates the additional column strength gained after transforming a given steel tube into a cable-stayed column.

Original language | English (US) |
---|---|

Pages | 195-210 |

Number of pages | 16 |

Volume | 54 |

No | 3 |

Specialist publication | Engineering Journal |

State | Published - Jan 1 2017 |

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### Keywords

- Analysis
- Behavior
- Buckling modes
- Cable (slackening, stays, optimum prestraining)
- Columns
- Cross-arms
- Design (ASD, LRFD)
- Eigenvectors
- Elastic stability
- Failure mode
- Load (applied, external)
- Numerical methods
- Residual tension
- Spring (augmented, parallel, series)
- Steel
- Stiffness probe
- Strength (enhancement, nominal)

### ASJC Scopus subject areas

- Civil and Structural Engineering
- Building and Construction

### Cite this

*Engineering Journal*,

*54*(3), 195-210.

**Analysis and design of cable-stayed steel columns using the stiffness probe method.** / Gurfinkel, German; Krishnan, Sudarshan.

Research output: Contribution to specialist publication › Article

*Engineering Journal*, vol. 54, no. 3, pp. 195-210.

}

TY - GEN

T1 - Analysis and design of cable-stayed steel columns using the stiffness probe method

AU - Gurfinkel, German

AU - Krishnan, Sudarshan

PY - 2017/1/1

Y1 - 2017/1/1

N2 - The stiffness probe method (SPM) is a new numerical procedure that calculates buckling loads. SPM probes the local stiffness of a given structure at the point of application of a small transverse perturbation force as the applied load is increased. The local stiffness degrades from a maximum for an unloaded structure to zero at the buckling load. An artifice spring is added to the original structure that eventually absorbs the full perturbation force at a prescribed small deflection, thereby keeping structural deformations small as the buckling load is approached. As a result, using an indicator that approaches zero at buckling rather than having to rely on increasingly larger deflections at buckling as in conventional P-Δ methods, SPM ensures an accurate numerical result for the critical load. We use SPM herein to study the behavior of one and two cross-arm cable-stayed columns under applied load. A formula is given to calculate the minimum slenderness that justifies converting a tube into a cable-stayed column. Various factors such as cable prestrain, cable cross-sectional areas, and tiers of cross-arms affecting column strength are examined for a series of cable-stayed columns. We find that cable-stayed columns may buckle either in a one-lobe symmetrical mode or two-lobe anti-symmetrical mode, the latter case being contrary to conventional thinking. A design example for a given cable-stayed column using the AISC Specification is presented. The effect of optimum cable prestrain to enhance column buckling strengths is discussed. A strength enhancement ratio (SER) is defined that evaluates the additional column strength gained after transforming a given steel tube into a cable-stayed column.

AB - The stiffness probe method (SPM) is a new numerical procedure that calculates buckling loads. SPM probes the local stiffness of a given structure at the point of application of a small transverse perturbation force as the applied load is increased. The local stiffness degrades from a maximum for an unloaded structure to zero at the buckling load. An artifice spring is added to the original structure that eventually absorbs the full perturbation force at a prescribed small deflection, thereby keeping structural deformations small as the buckling load is approached. As a result, using an indicator that approaches zero at buckling rather than having to rely on increasingly larger deflections at buckling as in conventional P-Δ methods, SPM ensures an accurate numerical result for the critical load. We use SPM herein to study the behavior of one and two cross-arm cable-stayed columns under applied load. A formula is given to calculate the minimum slenderness that justifies converting a tube into a cable-stayed column. Various factors such as cable prestrain, cable cross-sectional areas, and tiers of cross-arms affecting column strength are examined for a series of cable-stayed columns. We find that cable-stayed columns may buckle either in a one-lobe symmetrical mode or two-lobe anti-symmetrical mode, the latter case being contrary to conventional thinking. A design example for a given cable-stayed column using the AISC Specification is presented. The effect of optimum cable prestrain to enhance column buckling strengths is discussed. A strength enhancement ratio (SER) is defined that evaluates the additional column strength gained after transforming a given steel tube into a cable-stayed column.

KW - Analysis

KW - Behavior

KW - Buckling modes

KW - Cable (slackening, stays, optimum prestraining)

KW - Columns

KW - Cross-arms

KW - Design (ASD, LRFD)

KW - Eigenvectors

KW - Elastic stability

KW - Failure mode

KW - Load (applied, external)

KW - Numerical methods

KW - Residual tension

KW - Spring (augmented, parallel, series)

KW - Steel

KW - Stiffness probe

KW - Strength (enhancement, nominal)

UR - http://www.scopus.com/inward/record.url?scp=85073688909&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85073688909&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:85073688909

VL - 54

SP - 195

EP - 210

JO - Engineering Journal

JF - Engineering Journal

SN - 0013-8029

ER -