Design of timber elements

Objective

The objective is to verify and, if necessary, redesign a main beam of a floor composed of glued laminated timber beams arranged in parallel and evenly spaced. CLT panels are supported transversely on these beams, configured as two-span elements. The panels act as a rigid diaphragm, providing stability and preventing lateral-torsional buckling of the beams.

Students must carry out the verifications corresponding to the ULS and SLS of the proposed beam. In the process, they will need to calculate the critical acting stresses and identify the strength values to be applied, considering the modification and correction factors. For each specified load combinations, they must determine the corresponding utilization ratio. If the cross-sectional dimensions are found to be inadequate, they should propose a redesign to satisfy the required structural performance.

Tasks

This assignment is divided into three stages: 

1. Verification of resistance under persistent design situation

In this stage, the student must carry out checks of the beam’s bending and shear strength, as well as the bearing strength at the supports. For each verification, the student should select the appropriate span for calculation, according to the attached figure.

2. Verification of resistance under fire design situation

In this stage, the student must check the beam’s bending strength using the reduced section method. For this, the residual cross-section after the fire (effective section) should be considered. In this situation, checks for shear and perpendicular-to-grain compression at the supports are not required.

3. Verification of deflections

In this stage, the student must carry out checks for structural integrity, comfort, and appearance, taking into account material creep and the deflection component caused by shear stress.

Objective

The objective is to verify and, if necessary, redesign a façade column for an industrial building. The façade substructure consists of two-span horizontal elements that transfer loads to the columns, and is designed in such a way that it prevents buckling and lateral torsional instability of the column within the plane of the façade.

Students must perform the corresponding ULS verifications. In the process, they will have to calculate the governing internal forces, consider instability phenomena (buckling), and identify the strength values to be applied, considering the corresponding modification and correction factors. For each specified load combinations and sections, they must determine the corresponding utilization ratio. If the cross-sectional dimensions are found to be inadequate, they should propose a redesign to satisfy the required structural performance.

Tasks

This assignment is divided into two stages: 

1. Verification of cross-sectional resistance and member stability under persistent design situation

In this stage, the student must carry out sectional resistance checks for compression and flexural compression, as well as member stability checks considering the strength reductions due to buckling, for various load combinations. 

2. Verification of cross-sectional resistance and member stability under fire design situation 

In this phase, the student must perform checks of cross-sectional resistance and member stability, taking into account the residual cross-section after fire exposure (effective section).

Reference materials

• Design of timber estructures vol 2 - Rules and formulas according to Eurocode 5 | Swedish Wood (www.swedishwood.com). Chapter 5

• The Glulam Handbook vol 3 | Swedish Wood (www.swedishwood.com). Chapters 8-9, Example 6

• Columns | Structural Timber Education Program (https://e-step.net/)

• Buckling lengths | Structural Timber Education Program (https://e-step.net/)

The objective is to verify and, if necessary, design a large-span double-tapered glued laminated timber beam forming the roof of an industrial building. 

Students must carry out the ULS and SLS verifications of the proposed beam. In the process, they will need to calculate the critical acting stresses and identify the strength values to be applied, considering the modification and correction factors. For the specified load combination, they must determine the corresponding utilization ratio. If the cross-sectional dimensions are found to be inadequate, they should propose a redesign to satisfy the required structural performance.

Tasks

This assignment is divided into two stages: 

1. Verification of cross-sectional resistance and member stability under persistent design situation

In this stage, the student must carry out checks of the bending strength at the critical and midsections, the tensile strength perpendicular to the grain in the apex region, the compression perpendicular to grain and shear strengths at the supports, and the lateral-torsional buckling.

2. Verification of deflections

In this stage, the student must carry out checks for integrity and appearance, taking into account material creep and the deformation component caused by shear stress.