The COVID-19 pandemic poses an unprecedented challenge for the public transport system. The capacity of the transport system has been significantly reduced due to the imposition of social distancing measures to reduce the spread of the coronavirus. People remain skeptical about the use of public transport and prefer alternatives for their transportation as the likelihood of the virus spreading through public transport is high. Therefore, new avenues to increase the resilience of public urban mobility need to be explored. This research proposes the integration of the bike sharing system into the existing public transport system to compensate for public transport demand under the disruptive impacts of the COVID-19 pandemic. To achieve this, a two-part methodology is developed. The first part concerns the development of a mathematical model for the demand integration of the two systems. The demand for the public transport system, which cannot be serviced by the system due to the distancing measures (distance of 1.5 meters between passengers), is considered as unsatisfied demand and is the new additional demand for the bike sharing system. The second part concerns the development of an optimization model for the design and operation of a bike sharing system with features that can cope with the mobility needs of the pandemic. These features of the bike sharing system are the mixed fleet, i.e., the system will provide the mode options of bike and e-bike, and the hybrid in its design, i.e., the bike system will be a free-floating system while the e-bike system will be docked. The developed methodology is applied in the case study of the Milan city in Italy. The two studied systems are the subway system and the public bike sharing system of Milan. For the implementation of the developed methodology, three demand scenarios and fifteen designs that reflect the needs of the bike sharing system are created. The parameters that differ in the designs are the number and location of the new (virtual) stations, the number of the maximum number of available bikes in the virtual stations of the bike system and the capacity specifications (number of docks) in the e-bikes stations. The selected locations of the new (virtual) stations in the designs are close to subway stations with unsatisfied demand. The obtained results show that 30% of the demand for the evening peak hour of the subway system in Milan cannot be satisfied due to distancing measures and that the current public bike sharing system can only compensate for 6% of the new demand (unsatisfied demand of public transport system and its own demand). However, the mobility capacity increases based on the system’s features. The separation of the bike sharing system into a free-floating bike system and a docked e-bike system increases the covered demand at least twice (2.1-2.4 times). Moreover, an increase of the capacity specifications of the e-stations and the available bikes in virtual stations by 60% brings an additional increase of the covered demand by 6.5-7.5%. Despite the increased mobility capacity of the system with the incorporation of the mentioned features, to fully cover the bike system demand it is needed 30959 bikes, while 20445 e-bikes are needed for 70% coverage of e-bikes demand. In addition, there is no limit to the available bikes per station and the maximum number of docks per e-station is 200. It is concluded that the bike sharing system cannot fully counterbalance for limited capacity in the public transport system. These findings contribute worthwhile insights into the mobility capacity of the integrated public transport system during the pandemic and where the operators of both systems should give emphasis.