Video from my YouTube channel

Subscribe to My You tube channel

Types of Welds, Welding Positions, and Welding Joints Explained

By -

In steel structures and bridge construction, welding plays a critical role in ensuring the integrity and performance of the structure. Understanding the types of welds, welding positions, and joint configurations helps engineers and welders choose the most suitable welding method for each application. 

Types of Welds

There are three main types of welds commonly used in structural steel fabrication: fillet welds, groove welds, and slot or plug welds.


1. Fillet Welds

Fillet welds are the most common type of weld in structural applications. They are typically used when two members overlap, such as in T-joints, lap joints, or corner joints.

Fillet welds are economical, easy to perform, and provide adequate strength for most structural connections. They are widely used in bridges, buildings, and general fabrication work.

  • Strength Characteristics: Fillet welds perform well in tension and compression, but their shear resistance usually governs the design.

Whenever possible, arrange the connection so that the weld is subjected to shear only, rather than a combination of shear and tension/compression.

A slightly convex fillet weld is preferred because it helps reduce cracking during cooling. In contrast, concave welds may develop tensile stresses that increase the risk of surface cracks.

2. Groove Welds

Groove welds are formed when two members are joined edge to edge. They can be full-penetration or partial-penetration welds depending on the design requirements.

Groove welds are used in situations requiring high strength and complete fusion, such as:

  • Column splices

  • Beam flange to column connections

  • Critical joints in bridge girders

Although groove welds provide superior strength, they are less common (about 15% of structural welds) because they are more complex and costly to prepare and execute.

Depending on material thickness, different edge preparations are used:

  • Square groove joint (thin materials)

  • Single-V or Double-V groove joint (thicker materials)

  • U or J grooves (for thick plates where material saving is important)


A reinforcement of approximately 125–150% of the weld size is often provided to enhance static strength. However, in structures subjected to dynamic or vibrating loads, this reinforcement should be ground flush with the base material to avoid stress concentrations.

3. Slot and Plug Welds

Slot and plug welds are used to join one plate to another through holes or slots in one of the plates. These welds are not common in structural steelwork because their strength is limited and difficult to verify. They are generally used only for secondary connections or fabrication aids.

Welding Positions

Welds are also classified according to the position in which they are performed, which affects difficulty, quality, and welder qualification requirements.

  • Flat Position :
    The easiest and most common position, offering good control and quality.

  • Horizontal Position:
    Requires moderate skill; commonly used for fillet welds on structural members.

  • Vertical Position:
    More challenging due to gravity effects on molten metal; requires higher skill.

  • Overhead Position:
    The most difficult position; requires highly skilled and qualified welders due to difficulty maintaining proper bead shape and fusion.

Types of Welding Joints

The welding joint configuration defines how two parts are connected. The five basic joint types are:

  1. Butt Joint – Two members joined in the same plane, edge to edge.

  2. Tee Joint – One member is placed perpendicular to another (forming a “T”).

  3. Corner Joint – Two members joined at right angles to form an “L.”

  4. Lap Joint – One plate overlaps another.

  5. Edge Joint – Two adjacent edges of plates are joined.

Each joint type can accommodate fillet, groove, or plug welds depending on design requirements.

Welding Symbols

To simplify engineering drawings and reduce the need for long descriptive notes, standard welding symbols are used. These symbols convey essential information such as:

  • Type of weld (fillet, groove, plug, etc.)

  • Size and length of weld

  • Location (arrow side or other side)

  • Weld contour (flat, convex, concave)

  • Finishing requirements (e.g., grinding flush)

Using welding symbols ensures clear communication between designers, fabricators, and inspectors, saving both time and effort in fabrication and review.







 









 









Comments

Post a Comment

Videos from My Youtube channel

Popular posts from this blog

Pile cap

By -
Image
Pile cap used to transfer the loads from superstructure to the piling. The pile cap is thick concrete mat rests on piles. It is part of the foundation and used to distribute the loads over the piles. Piles used when the soil bearing is not enough to carry loads of the structure. Figure 1  construction management: concrete construction bridge construction:How to become a bridge engineer Pile cap construction procedure Excavation around piles: After 7 days of the casting of the pile the concrete will gain approximately, 70% of it is compressive strength. The soil around piles will be removed to the required levels and dimension that allows construction of the pile cap. A step shall be made if the excavation is more than 1.5 m to prevent soil collapse. Figure 2 Pile head cutting: Concrete will be removed up to cut off level. If concrete under the cut off level is unsound. It shall be removed, and the pile will be repaired...
Read more

Bridge Diaphragm

By -
Image
The main function of diaphragms is to provide a stiffening effect to deck slab in case bridge webs are not situated directly on top of bearings. Therefore, diaphragms may not be necessary in case bridge bearings are placed directly under the webs because loads in bridge decks can be directly transferred to the bearings.On the other hand, diaphragms also help to improve the load-sharing characteristics of bridges. Diaphragms also contribute to the provision of torsional restraint to the bridge deck. Diaphragm will be used also to resist stresses that occurs during the post-tensioning process. Post-tensioning hardware are casted inside the diaphragm. Figure 1 construction management: concrete construction bridge construction:How to become a bridge engineer Types of diaphragm: Diaphragm at the span end: this type of diaphragms will be located between two bridge spans or at the bridge abutments. Expansion joints will be used to connect bridge spans. This ...
Read more

Moment Diagrams Constructed by the Method of Superposition

By -
Image
Shear and moment diagrams are very important to conduct a structural analysis for a member or structure. Also, the designer should know the shear and moment values applied to a member to determine the amount of reinforcement and member dimension. A structural engineer should have the ability to draw shear and moment diagrams . Superposition is one of the methods used to draw the moment diagram. In this method, the loads applied on beam taken individually. The moment diagram for each load drawn separately. The moment diagram for a beam is the sum of these diagrams for each load case. Figure 1 shows most of the load cases for a beam. Figure 1 To understand the principle of superposition let consider the simply supported beam in figure 2. the simply supported beam in figure 2 subjected to a distributed load of 4k/ft over half of the beam and moment of 300 k.ft at the middle of the beam. First, we will calculate the reaction at support A and B. for simpl...
Read more

Repairing of concrete bulging

By -
Image
Improper designing and installation of formwork for a concrete member can result in concrete Bulging. During the placing and compacting of concrete, forms may deflect largely in the weak areas. The deflection of forms will cause concrete to expand at this location, and this known as concrete Bulging. Concrete Bulging will spoil the appearance of a concrete member. Therefore we should always ensure that the forms are appropriately installed, and it is sufficiently supported to resist the concrete during placing and compacting. Bulging should be repaired in case we couldn't avoid it. The solution of concrete Bulging, offset, or surface irregularities are surface grinding. However, excessive surface grinding can weaken the concrete.  Figure 1 If the bulging or surface irregularities are small, grinding of concrete surface will be sufficient to remove surface irregularities. If the Bulging of concrete is significant, then the concrete should be chipped, and the surface...
Read more

wing wall arrangement and orientation for abutments

By -
Image
wing wall main function is to retain the embankment near abutment. the common slope is 2:1. greater than 2:1 is not allowed. figure no: shows a wing wall for the abutment. Figure 1  there is three arrangement for wing wall: wing wall parallel to abutment: easy to build. construction can be done in a short time. this type of wing wall will not disturb the existing embankment and utilities but it is not the most economical arrangement.   figure 2 construction management: concrete construction bridge construction:How to become a bridge engineer wing wall at an angle with abutments: this type is most economical among the three arrangement. Figure 3 wing wall perpendicular to abutment: in this arrangement. wing wall provides a continuous alignment with bridge deck which can be used to support parapets. this arrangement will disturb existing embankment and utilities adjacent to the structure. for curve bridge, this type o...
Read more

ACI Reinforcement Limits Explained: Minimum and Maximum Steel Area for Concrete Columns

By -
Image
According to ACI, the area of longitudinal reinforcement for a column shall not be less than 0.01·Ag and shall not exceed 0.08·Ag (Ag = gross sectional area of the column). The minimum reinforcement requirement ensures the column has sufficient reinforcement to resist bending that may arise from misalignment during construction or other causes, and to control shrinkage and creep under sustained load. The maximum reinforcement limit of 8% is intended to prevent overly brittle behavior and sudden failure without warning. A very large amount of reinforcement also causes congestion, making proper placement of bars, ties, and concrete consolidation impractical. The 8% limitation applies to the total longitudinal area at a section — the designer must therefore consider column length, bar lengths, splice locations, and lap splice practices when checking the maximum reinforcement criterion. Example (60 cm × 40 cm column) Gross area: Ag = 600 mm × 400 mm = 240,000 mm². Minimum longitudinal...
Read more

Types and Classifications of Bolts and Bolted Connections in Steel Structures

By -
Image
Bolts are one of the most essential components in steel construction. They connect individual structural members, transfer loads, and ensure overall stability. Understanding the different types of bolts , their strength grades , and connection classifications is critical for safe and efficient structural design and erection. 1. Classification of Bolts Bolts used in steel structures are generally divided into two main categories: 1.1 Unfinished (Common) Bolts These are low-strength bolts commonly used in secondary structural elements such as bracing, purlins, and temporary connections. They are economical and suitable where loads are relatively small and precision tightening is not critical. 1.2 High-Strength Bolts High-strength bolts are designed for primary structural connections such as beam-to-column joints, truss connections, and bridge girders. According to the ASTM (American Society for Testing and Materials), they are mainly classified as: ASTM A325: Medium carbon ...
Read more

Prestressing stands debonding

By -
Image
  Prestressing bridge concrete beams contributes to resisting the tensile stresses caused by the traffic loads and the beam's weight. Stressing concrete has various benefits, such as increasing concrete members' capacity, reducing the concrete member section, and increasing the span lengths for structures such as bridges and buildings. However,  The stressing of bridge beam ends can result in unwanted cracks. Therefore AASHTO calling for debonding a specific portion of strands at the beam end to minimize the stresses and reduce cracks. Figure 1 Debonding is achieved by wrapping the strands at the end of the beam with plastic. Wrapping the strand with plastic wrapping will prevent the strands from bonding with concrete, thus avoid transferring unwanted stress to the beam end. As a result, the unwanted cracks will be prevented by reducing the stress levels at the end of the beam.  
Read more

Flakiness Index and Elongation Index of Coarse Aggregates

By -
Image
Flaky and elongated aggregates can adversely affect concrete. Flaky and elongated aggregates are difficult to compact. Therefore using flaky and elongated aggregates will reduce concrete workability, which required more amount of water to produce a workable mix. Increasing water content will reduce concrete strength and durability. Moreover, these aggregates are not robust, which leads to lowering concrete strength. Figure 1 construction management: concrete construction bridge construction:How to become a bridge engineer The Flakiness Index of aggregates is the percentage by weight of particles whose least dimension (thickness) is less than three- fifths (0.6times) of their mean dimension. This test does not apply to sizes smaller than 6.3mm. The Elongation index of an aggregate is the percentage by weight of particles whose greatest dimension (length) is greater than nine-fifths (1.8times) their mean dimension. Flakiness and elongation tests ar...
Read more