bILL bOARD

admin — Thu, 09 Dec 2021 02:41:26 +0000

Executive Summary

The purpose of this project is to design and analyze the structure of the billboard used for marketing.

A billboard is extremely lucrative real estate that could be rented at high ROI margins.

Process

Research

Firstly, we research, this includes, what is the market standard of manufacturing billboards, how are they used, the types of materials and a brief understanding of the market.

Firstly, we determine a design considering the requirements of the industry standard of a 48 ft x 14 ft billboard. We considered the columns that will support the billboard 20 ft off the ground. Then we can not forget to consider the foundation.

We must sketch the forces and pressures and have an estimate of where these loads are going to be applied.

For the geometry firstly we make that we are hitting all the requirements listed by client. Then everything else is to be assumed based on standards and technical expertise.

Material Properties

After we have a Rough Design, we review the material properties of material and estimate if these materials can handle the pressures being applied.

This billboard could have been built out of anything included wooden poles and frames or steel, but this largely came down to cost. Since the client did not specific a budget, we will go with the most expensive design which will be made from steel.

Ansys Simulation

We then simulated our design on Ansys ADPL and tested our initial design based on the physics and engineering preprogrammed in the software.

Interpretation of results

We found all the stresses and deflections in the structure to be essentially nonexistent based on the estimates and provided requirements. We also tested the effect of vibrations and thermal loading which was also found to be negligible.

MAX Stress = 242 psi

Max Deflection = .002792 inches

Sketches

No.	Material	Explanation
1	Steel	Structural steel is important for the columns that support the entire structure. This is important this because this is where most of the loads are going to be transmitted to the foundation. This is also critical to because this is the area where the structure is absorbs the wind force. Steel is also used for the for the panels of the billboard where the billboard advertisements are placed.
2	Concrete	Concrete is chosen because of its cost and safety factors that are required of building a strong foundation.
3	PVC	PVC is chosen for the Board because of the lightness and malleability. (Excluded from simulation)

Materials

	Material Properties Table
No.	Material Name	E(e6psi)	Poisson Ratio	Alpha (e-6 in/in F)	Density (lb/in^3)
1	Structural Steel	29	.32	6	0.283
2	PVC	0.4	0.4	30	0.050
3	Concrete	10	.2	7.22	0.0867

These are the materials that I chose because of the standards associated with building billboards. There are many materials to choose from and this is largely dependant on cost.

Elements

No.	Element	Reasoning
1	Plane 183 with thick	The other elements have the condition of with thick. Real Constants One with a thickness of 120 inches to simulate a 3D foundation Second Element has a thickness of 24 inches to represent the thickness of the steel billboard.
2	Plane 183 with axis symmetry	One element has an axis symmetry condition for the round columns. This so the column can support the weight of the beam and would not just be thin plates.

Boundary Conditions

A boundary condition was applied to the entire left side of the structure which will restrain its movement in all directions. All the elements were glued together so that boundary condition should be sufficient for the entire structure.

Assumptions

We exclude the PVC material because it’s weight and attachment are negligible

One large panel transmits the same loads as panels joined to together

We will assume the bolts and components that support the advertisement are negligible

The focus in on the overall structure not the subcomponents for example the frame that usually supports individual panels.

Assume that the wind is only blowing in one direction.

We assume that foundation is filled with concrete after the holes are dug for the columns to support the board.

The weight of the board and lighting can be simulated with one distributed load

Loads

The loads being the structure are going to be a wind load of 20 lbs / ft (1.66 lbs/inch) on the front face of the billboard and the Steel supporting columns, it is assumed that the wind is blowing in one direction and all the loads will be transmitted to the foundation.

Also, a load of 10,000 lbs with be used to simulate the weight of the billboard, the lighting, and any operators on the structure. This load will be converted to a distribute load of 17 lbs/inch and will be applied on the top of the structure to be transmitted through out.

Method

I will be using Ansys ADPL to simulate the design because it is easy and a lightweight software to do the calculations required. There are limitations to the student version of the software, like the number of acceptable nodes so the meshing will be less accurate than the full version.

Mesh

The mesh applied was an area mesh with a quad shape and 2^nd order type of mesh. The size of the mesh was left to the Ansys software to create a medium sized mesh because there were too many nodes if we divided the elements too much. Even if the element was divided and used a symmetry boundary condition. A mesh refinement was applied after we identified the higher stress area.

Presentations of Model

Geometrical Model

This model shows all the pressures and boundary conditions of the model.

Deformed Model

The stresses barely affect the design.

Displacement Vector Distribution Plot

The maximum deflection of this model is .002792 inches, and all the forces seem to pass from the billboard through and to the foundation which is what is expected and required.

The Maximum deflection is found where the billboard over hangs

Von Mises Plot

Based on this design the Max stress acting on the model was 242 psi which is extremely low as the yield strength of the steel billboard and columns is 36000 psi. The effects of the wind and the weight of the board of the lighting has negligible effects on the structure so the design requirements are met.

Using a standard Factor of safety of 1.5 for the build the max allowable stress 36000psi/1.5 =24000psi.

Which means the designs satisfies the requirements.

The Max Deflection is found where the billboard and the columns are joined which are common stress points.

Modal and Thermal Analysis

Based on the vibration study results, vibrations have a negligible effect on this structure based on frequencies ranging from .312058 Hz to 1.96278 Hz

The max deflection is also negligible going from .352e-3 in to .681 e – 03 in

Thermal

Also, a change of 20 degrees was applied to the structure which marginal changed the stresses acting on the design.

Analysis

All the explanations and interpretation of the models are listed below their respective presentations of the models.

Cost

The expected cost of this design will be about is 50-60 thousand because of the cost of the materials, which the most expensive parts is the steel structure. And cost of labour which requires and entire crew of people to construct.

Conclusions

The design of billboards is extremely lucrative industry where billboard designs are always required, this is especially interesting that the structural design and requirements are not as complex as most people will assume.

Rondon's Portfolio

bILL bOARD

Sketches