In　this　paper,　an　improved　type　of　beam-to-column　joint　was　proposed　to　enhance　the　material　efficiency　and　structural　behaviour　of　typical　welded　unstiffened　flange-bolted　web　(WUF-B)　joints,　where　the　thickness　of　the　flange　on　the　beam　was　varied　using　longitudinally　profiled　(LP)　plates.　LP　plates　are　plates　manufactured　to　various　thickness　along　the　rolling　direction　to　optimise　their　design　under　different　loading　distributions.　Three　full-scale　beam-to-column　WUFB　joints　with　LP　plates　were　designed　and　tested　under　cyclic　load.　Different　thickness　change　ratios　and　lengths　of　the　variable　thickness　were　considered　in　the　specimen　design.　The　obtained　moment-rotation　curves　and　the　failure　modes　of　the　specimens　were　reported.　Compared　with　a　conventional　WUF-B　joint,　it　was　found　that　the　moment　capacity　of　the　joints　can　be　significantly　improved　as　a　consequence　of　higher　material　efficiency.　As　WUF-B　joints　tend　to　fail　from　brittle　weld　metal　fractures,　micromechanical　fracture　model　of　cyclic　void　growth　model　(CVGM)　was　incorporated　in　the　numerical　models　developed　herein　to　predict　the　joint　failure.　A　subsequent　parametric　study　was　carried　out,　considering　a　range　of　LP　flange　lengths　and　thickness　change　ratios　as　an　extension　of　the　tests.　It　was　found　that　designing　the　improved　WUF-B　joints　with　a　short　LP　flange　length　and　a　high　thickness　change　ratio　can　enhance　the　plastic　rotation　capacities　and　avoid　brittle　failure.