- l-box
- laboratory
- labourer
- landing
- lap
- lap joint
- lap length
- lap splice
- lap weld
- lapping
- latent hydraulic
- lateral area
- lateral buckling
- lateral contraction
- lateral force
- lateral loading
- lateral-torsional buckling
- lattice framework
- lattice girder
- lattice theory
- layer of reinforcement
- leading action
- lean concrete
- leg
- length
- letting (of a contract)
- level
- lever arm
- lever arm, internal
- life
- lifting appliance
- lifting eye
- lightweight aggregate
- lightweight concrete
- lime
- lime efflorescence
- limestone
- limestone efflorescence
- limit of proportionality
- limit state
- limit state design
- limit states
- limit states method
- line of action
- line of pressure
- line of thrust
- linear
- linear analysis
- linear bearing
- linear compression member
- linear elastic analysis
- linear elastic theory
- linear element
- linear load
- link
- lintel
- liquid-retaining structure
- live load(ing)
- load
- load (-carrying) capacity
- load arrangement
- load carrying
- load case
- load cell
- load combination
- load condition, static
- load cycle
- load introduction
- load introduction area
- load path
- load specification
- load train
- load transferring
- load-bearing wall
- loadbearing capacity
- loaded area
- loaded length
- loading
- local buckling
- local reinforcement
- lock
- lock-nut
- locking jack
- logarithmic
- long duration action
- long term effect
- long term influence
- long term relaxation
- long term value
- long-term effect
- long-term loading
- long-term test
- longitudinal axis
- longitudinal bar
- longitudinal bending reinforcement
- longitudinal compression
- longitudinal crack
- longitudinal force
- longitudinal girder
- longitudinal prestressing
- longitudinal reinforcement
- longitudinal reinforcement ratio
- longitudinal section
- longitudinal shear
- longitudinal shear force
- longitudinal spacing
- longitudinal tensile reinforcement
- longitudinal tension reinforcement
- longitudinal torsion steel
- longitudinal weld
- loop
- loop anchorage
- loss of fines
- loss of prestress
- loss of stress
- loss on ignition
- low bond action
- lower bound plastic solution
- lower characteristic value
- lower face