Angle sections are the most widely used shapes for making built-up sections and also the standard section used for primary members of lattice towers. Retrofit of transmission line towers are done by attaching an additional angle to existing members among which the most efficient built-up geometry reported in literature is a built-up bi-angled cruciform. While studies on the behavior of built-up bi-angled cruciform are present in literature, analysis of any built-up sections used for retrofitting should include the load in the existing member before the attachment of the strengthening member. This study presents a numerical investigation to determine the behavior of the bi-angled cruciforms under pre-load and the load sharing between the two angles by developing 60 models in ABAQUS. Existing load magnitudes of 0, 25, 50, 75 and 100% of its design compressive strength (as per IS 800-2007) for three different slenderness ratios of 80, 100 and 120 are included. From the study it was found that the stiffness and ultimate load of bi-angled cruciform section were not vary much with pre-load magnitude. The load sharing between the existing and strengthening members for all models was found to be highest when existing load is 75% of design compressive strength.